diff --git a/examples/vanilla_client/src/server.rs b/examples/vanilla_client/src/server.rs
index f2f4677c89..8ad04dfb62 100644
--- a/examples/vanilla_client/src/server.rs
+++ b/examples/vanilla_client/src/server.rs
@@ -32,8 +32,8 @@ pub fn server(
         username: USERNAME.to_string(),
         client_seed: seed_value,
         client_proof,
-        decompressed_addon_info_size: 0,
-        compressed_addon_info: vec![],
+        decompressed_addon_info_size: 342,
+        addon_info: vec![66, 108, 105, 122, 122, 97, 114, 100, 95, 65, 117, 99, 116, 105, 111, 110, 85, 73, 0, 1, 109, 119, 28, 76, 0, 0, 0, 0, 66, 108, 105, 122, 122, 97, 114, 100, 95, 66, 97, 116, 116, 108, 101, 102, 105, 101, 108, 100, 77, 105, 110, 105, 109, 97, 112, 0, 1, 109, 119, 28, 76, 27, 223, 5, 165, 66, 108, 105, 122, 122, 97, 114, 100, 95, 66, 105, 110, 100, 105, 110, 103, 85, 73, 0, 1, 109, 119, 28, 76, 0, 0, 0, 0, 66, 108, 105, 122, 122, 97, 114, 100, 95, 67, 111, 109, 98, 97, 116, 84, 101, 120, 116, 0, 1, 109, 119, 28, 76, 27, 223, 5, 165, 66, 108, 105, 122, 122, 97, 114, 100, 95, 67, 114, 97, 102, 116, 85, 73, 0, 1, 109, 119, 28, 76, 0, 0, 0, 0, 66, 108, 105, 122, 122, 97, 114, 100, 95, 71, 77, 83, 117, 114, 118, 101, 121, 85, 73, 0, 1, 109, 119, 28, 76, 27, 223, 5, 165, 66, 108, 105, 122, 122, 97, 114, 100, 95, 73, 110, 115, 112, 101, 99, 116, 85, 73, 0, 1, 109, 119, 28, 76, 0, 0, 0, 0, 66, 108, 105, 122, 122, 97, 114, 100, 95, 77, 97, 99, 114, 111, 85, 73, 0, 1, 109, 119, 28, 76, 27, 223, 5, 165, 66, 108, 105, 122, 122, 97, 114, 100, 95, 82, 97, 105, 100, 85, 73, 0, 1, 109, 119, 28, 76, 0, 0, 0, 0, 66, 108, 105, 122, 122, 97, 114, 100, 95, 84, 97, 108, 101, 110, 116, 85, 73, 0, 1, 109, 119, 28, 76, 27, 223, 5, 165, 66, 108, 105, 122, 122, 97, 114, 100, 95, 84, 114, 97, 100, 101, 83, 107, 105, 108, 108, 85, 73, 0, 1, 109, 119, 28, 76, 0, 0, 0, 0, 66, 108, 105, 122, 122, 97, 114, 100, 95, 84, 114, 97, 105, 110, 101, 114, 85, 73, 0, 1, 109, 119, 28, 76, 27, 223, 5, 165],
     }
     .write_unencrypted_client(stream)
     .unwrap();
diff --git a/intermediate_representation.json b/intermediate_representation.json
index f2a468ec33..822a2ed2c5 100644
--- a/intermediate_representation.json
+++ b/intermediate_representation.json
@@ -94790,7 +94790,7 @@
         {
           "type": "definition",
           "content": {
-            "name": "compressed_addon_info",
+            "name": "addon_info",
             "member_type": {
               "type": "array",
               "content": {
@@ -94808,7 +94808,9 @@
             "constant_value": null,
             "used_as_size_in": null,
             "used_in_if": false,
-            "tags": {}
+            "tags": {
+              "compressed": "decompressed_addon_info_size"
+            }
           }
         }
       ],
@@ -94925,141 +94927,353 @@
               "tags": {}
             },
             {
-              "variable_name": "compressed_addon_info",
+              "variable_name": "addon_info",
               "value": {
                 "type": "array",
                 "content": {
                   "values": [
-                    120,
-                    156,
+                    66,
+                    108,
+                    105,
+                    122,
+                    122,
+                    97,
+                    114,
+                    100,
+                    95,
+                    65,
                     117,
-                    204,
-                    189,
-                    14,
-                    194,
-                    48,
-                    12,
-                    4,
-                    224,
-                    242,
-                    30,
-                    188,
-                    12,
+                    99,
+                    116,
+                    105,
+                    111,
+                    110,
+                    85,
+                    73,
+                    0,
+                    1,
+                    109,
+                    119,
+                    28,
+                    76,
+                    0,
+                    0,
+                    0,
+                    0,
+                    66,
+                    108,
+                    105,
+                    122,
+                    122,
                     97,
-                    64,
-                    149,
-                    200,
+                    114,
+                    100,
+                    95,
                     66,
-                    195,
-                    140,
+                    97,
+                    116,
+                    116,
+                    108,
+                    101,
+                    102,
+                    105,
+                    101,
+                    108,
+                    100,
+                    77,
+                    105,
+                    110,
+                    105,
+                    109,
+                    97,
+                    112,
+                    0,
+                    1,
+                    109,
+                    119,
+                    28,
                     76,
-                    226,
-                    34,
-                    11,
-                    199,
-                    169,
-                    140,
-                    203,
-                    79,
-                    159,
-                    30,
-                    22,
-                    36,
-                    6,
-                    115,
-                    235,
+                    0,
+                    0,
+                    0,
+                    0,
+                    66,
+                    108,
+                    105,
+                    122,
+                    122,
+                    97,
+                    114,
+                    100,
+                    95,
+                    66,
+                    105,
+                    110,
+                    100,
+                    105,
+                    110,
+                    103,
+                    85,
+                    73,
+                    0,
+                    1,
+                    109,
                     119,
+                    28,
+                    76,
+                    0,
+                    0,
+                    0,
+                    0,
+                    66,
+                    108,
+                    105,
+                    122,
+                    122,
+                    97,
+                    114,
+                    100,
+                    95,
+                    67,
+                    111,
+                    109,
+                    98,
+                    97,
+                    116,
+                    84,
+                    101,
+                    120,
+                    116,
+                    0,
+                    1,
+                    109,
                     119,
-                    129,
+                    28,
+                    76,
+                    0,
+                    0,
+                    0,
+                    0,
+                    66,
+                    108,
                     105,
-                    89,
-                    64,
-                    203,
+                    122,
+                    122,
+                    97,
+                    114,
+                    100,
+                    95,
+                    67,
+                    114,
+                    97,
+                    102,
+                    116,
+                    85,
+                    73,
+                    0,
+                    1,
+                    109,
+                    119,
+                    28,
+                    76,
+                    0,
+                    0,
+                    0,
+                    0,
+                    66,
+                    108,
                     105,
-                    51,
-                    103,
-                    163,
-                    38,
-                    199,
-                    190,
-                    91,
-                    213,
-                    199,
                     122,
-                    223,
-                    125,
-                    18,
-                    190,
-                    22,
-                    192,
-                    140,
-                    113,
-                    36,
-                    228,
-                    18,
+                    122,
+                    97,
+                    114,
+                    100,
+                    95,
+                    71,
+                    77,
+                    83,
+                    117,
+                    114,
+                    118,
+                    101,
+                    121,
+                    85,
                     73,
-                    168,
-                    194,
-                    228,
-                    149,
-                    72,
-                    10,
-                    201,
-                    197,
-                    61,
-                    216,
-                    182,
+                    0,
+                    1,
+                    109,
+                    119,
+                    28,
+                    76,
+                    0,
+                    0,
+                    0,
+                    0,
+                    66,
+                    108,
+                    105,
                     122,
-                    6,
-                    75,
-                    248,
-                    52,
-                    15,
-                    21,
-                    70,
+                    122,
+                    97,
+                    114,
+                    100,
+                    95,
+                    73,
+                    110,
                     115,
-                    103,
-                    187,
-                    56,
-                    204,
+                    112,
+                    101,
+                    99,
+                    116,
+                    85,
+                    73,
+                    0,
+                    1,
+                    109,
+                    119,
+                    28,
+                    76,
+                    0,
+                    0,
+                    0,
+                    0,
+                    66,
+                    108,
+                    105,
                     122,
-                    199,
-                    151,
-                    139,
-                    189,
-                    220,
-                    38,
-                    204,
-                    254,
-                    48,
+                    122,
+                    97,
+                    114,
+                    100,
+                    95,
+                    77,
+                    97,
+                    99,
+                    114,
+                    111,
+                    85,
+                    73,
+                    0,
+                    1,
+                    109,
+                    119,
+                    28,
+                    76,
+                    0,
+                    0,
+                    0,
+                    0,
                     66,
-                    214,
-                    230,
-                    202,
+                    108,
+                    105,
+                    122,
+                    122,
+                    97,
+                    114,
+                    100,
+                    95,
+                    82,
+                    97,
+                    105,
+                    100,
+                    85,
+                    73,
+                    0,
                     1,
-                    168,
-                    184,
-                    144,
-                    128,
-                    81,
-                    252,
-                    183,
-                    164,
-                    80,
-                    112,
-                    184,
-                    18,
-                    243,
-                    63,
-                    38,
-                    65,
-                    253,
-                    181,
-                    55,
-                    144,
-                    25,
-                    102,
-                    143
+                    109,
+                    119,
+                    28,
+                    76,
+                    0,
+                    0,
+                    0,
+                    0,
+                    66,
+                    108,
+                    105,
+                    122,
+                    122,
+                    97,
+                    114,
+                    100,
+                    95,
+                    84,
+                    97,
+                    108,
+                    101,
+                    110,
+                    116,
+                    85,
+                    73,
+                    0,
+                    1,
+                    109,
+                    119,
+                    28,
+                    76,
+                    0,
+                    0,
+                    0,
+                    0,
+                    66,
+                    108,
+                    105,
+                    122,
+                    122,
+                    97,
+                    114,
+                    100,
+                    95,
+                    84,
+                    114,
+                    97,
+                    100,
+                    101,
+                    83,
+                    107,
+                    105,
+                    108,
+                    108,
+                    85,
+                    73,
+                    0,
+                    1,
+                    109,
+                    119,
+                    28,
+                    76,
+                    0,
+                    0,
+                    0,
+                    0,
+                    66,
+                    108,
+                    105,
+                    122,
+                    122,
+                    97,
+                    114,
+                    100,
+                    95,
+                    84,
+                    114,
+                    97,
+                    105,
+                    110,
+                    101,
+                    114,
+                    85,
+                    73,
+                    0,
+                    1,
+                    109,
+                    119,
+                    28,
+                    76,
+                    0,
+                    0,
+                    0,
+                    0
                   ],
                   "size": {
                     "type": "endless"
@@ -95483,7 +95697,7 @@
         {
           "type": "definition",
           "content": {
-            "name": "compressed_addon_info",
+            "name": "addon_info",
             "member_type": {
               "type": "array",
               "content": {
@@ -95501,7 +95715,9 @@
             "constant_value": null,
             "used_as_size_in": null,
             "used_in_if": false,
-            "tags": {}
+            "tags": {
+              "compressed": "decompressed_addon_info_size"
+            }
           }
         }
       ],
@@ -95525,7 +95741,7 @@
       "tests": [],
       "file_info": {
         "file_name": "wow_message_parser/wowm/world/character_screen/cmsg_auth_session.wowm",
-        "start_position": 70
+        "start_position": 101
       },
       "only_has_io_error": false,
       "features": [
diff --git a/wow_message_parser/src/ir_printer/mod.rs b/wow_message_parser/src/ir_printer/mod.rs
index 7ebcf1e0b1..4ae21bc8a9 100644
--- a/wow_message_parser/src/ir_printer/mod.rs
+++ b/wow_message_parser/src/ir_printer/mod.rs
@@ -139,6 +139,8 @@ pub(crate) struct IrTags {
     version: Option<IrVersions>,
     #[serde(skip_serializing_if = "Option::is_none")]
     unimplemented: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    compressed: Option<String>,
 }
 
 impl IrTags {
@@ -147,6 +149,8 @@ impl IrTags {
 
         let comment = tags.comment().map(|d| d.as_ir_string());
 
+        let compressed = tags.compressed().map(|d| d.to_string());
+
         let unimplemented = if tags.contains("unimplemented") {
             Some("true".to_string())
         } else {
@@ -168,6 +172,7 @@ impl IrTags {
             } else {
                 None
             },
+            compressed,
             unimplemented,
         }
     }
diff --git a/wow_message_parser/src/main.rs b/wow_message_parser/src/main.rs
index cf2c62c734..85900aae39 100644
--- a/wow_message_parser/src/main.rs
+++ b/wow_message_parser/src/main.rs
@@ -46,6 +46,7 @@ const UTILITY_PATH: &str = "crate::util";
 
 const VERSIONS: &str = "versions";
 const DESCRIPTION: &str = "description";
+const COMPRESSED: &str = "compressed";
 const COMMENT: &str = "comment";
 const DISPLAY: &str = "display";
 const TEST_STR: &str = "test";
diff --git a/wow_message_parser/src/parser/types/tags.rs b/wow_message_parser/src/parser/types/tags.rs
index 3e38d8038f..0a1e1c2296 100644
--- a/wow_message_parser/src/parser/types/tags.rs
+++ b/wow_message_parser/src/parser/types/tags.rs
@@ -4,7 +4,7 @@ use std::fmt::{Display, Formatter, Write};
 use crate::file_utils::get_import_path;
 use crate::rust_printer::Version;
 use crate::{
-    Objects, COMMENT, DESCRIPTION, DISPLAY, LOGIN_VERSIONS, RUST_BASE_TYPE, TEST_STR, VERSIONS,
+    Objects, COMMENT, DESCRIPTION, COMPRESSED, DISPLAY, LOGIN_VERSIONS, RUST_BASE_TYPE, TEST_STR, VERSIONS,
 };
 
 #[derive(Debug, Eq, PartialEq, Copy, Clone)]
@@ -240,6 +240,7 @@ pub(crate) struct Tags {
     login_logon_versions: Vec<LoginVersion>,
     world_versions: Vec<WorldVersion>,
     description: Option<TagString>,
+    compressed: Option<String>,
     comment: Option<TagString>,
     display: String,
 }
@@ -323,6 +324,8 @@ impl Tags {
                 t.add(value);
                 self.description = Some(t);
             }
+        } else if key == COMPRESSED {
+            self.compressed = Some(value.to_owned());
         } else if key == COMMENT {
             if let Some(comment) = &mut self.comment {
                 comment.add(value);
@@ -535,6 +538,14 @@ impl Tags {
         self.description.as_ref()
     }
 
+    pub(crate) fn compressed(&self) -> Option<&String> {
+        self.compressed.as_ref()
+    }
+
+    pub(crate) fn is_compressed(&self) -> bool {
+        self.compressed.is_some()
+    }
+
     pub(crate) fn comment(&self) -> Option<&TagString> {
         self.comment.as_ref()
     }
diff --git a/wow_message_parser/src/rust_printer/structs/print_common_impls/mod.rs b/wow_message_parser/src/rust_printer/structs/print_common_impls/mod.rs
index c1007a7257..275b268da6 100644
--- a/wow_message_parser/src/rust_printer/structs/print_common_impls/mod.rs
+++ b/wow_message_parser/src/rust_printer/structs/print_common_impls/mod.rs
@@ -191,12 +191,17 @@ pub(crate) fn print_size_of_ty_rust_view(s: &mut Writer, m: &RustMember, prefix:
                         ty = integer_type.rust_str(),
                     ),
                     ArraySize::Variable(_) | ArraySize::Endless => {
-                        format!(
-                            "{prefix}{name}.len() * core::mem::size_of::<{ty}>()",
-                            name = m.name(),
-                            prefix = prefix,
-                            ty = integer_type.rust_str(),
-                        )
+                        // ZLib compression is not predictable, so we compress the data and count the bytes.
+                        if m.tags().is_compressed() {
+                            format!("crate::util::zlib_compressed_size(&{prefix}{name})", prefix = prefix, name = m.name())
+                        } else {
+                            format!(
+                                "{prefix}{name}.len() * core::mem::size_of::<{ty}>()",
+                                name = m.name(),
+                                prefix = prefix,
+                                ty = integer_type.rust_str(),
+                            )
+                        }
                     }
                 },
                 ArrayType::Complex(_) => match array.size() {
diff --git a/wow_message_parser/src/rust_printer/structs/print_common_impls/print_read.rs b/wow_message_parser/src/rust_printer/structs/print_common_impls/print_read.rs
index dd46f0abcf..d62b29b945 100644
--- a/wow_message_parser/src/rust_printer/structs/print_common_impls/print_read.rs
+++ b/wow_message_parser/src/rust_printer/structs/print_common_impls/print_read.rs
@@ -285,6 +285,29 @@ fn print_read_array(
                 s.wln("current_size += 1;");
             });
             s.newline();
+
+            if let Some(decompresssed_size_field) = d.tags().compressed() {
+                let decompressed_name = format!("{}_temp", d.name());
+
+                s.wln(format!(
+                    "let mut {temp_field} = Vec::with_capacity({decompressed_size} as usize);",
+                    temp_field = decompressed_name, decompressed_size = decompresssed_size_field
+                ));
+                s.wln(format!(
+                    "let mut decoder = flate2::read::ZlibDecoder::new({field}.as_slice());",
+                    field = d.name()
+                ));
+                s.wln(format!(
+                    "decoder.read_to_end(&mut {temp_field})?;",
+                    temp_field = decompressed_name
+                ));
+                s.newline();
+                s.wln(format!(
+                    "let mut {field} = {temp_field};",
+                    field = d.name(), temp_field = decompressed_name
+                ));
+                s.newline();
+            }
         }
     }
 }
diff --git a/wow_message_parser/src/rust_printer/structs/print_common_impls/print_write.rs b/wow_message_parser/src/rust_printer/structs/print_common_impls/print_write.rs
index b9c645cea9..01d1fdcc69 100644
--- a/wow_message_parser/src/rust_printer/structs/print_common_impls/print_write.rs
+++ b/wow_message_parser/src/rust_printer/structs/print_common_impls/print_write.rs
@@ -25,23 +25,30 @@ pub(crate) fn print_unencrypted_write_header(s: &mut Writer, e: &Container, post
 
 pub(crate) fn print_write_field_array(
     s: &mut Writer,
-    variable_name: &str,
+    d: &StructMemberDefinition,
     variable_prefix: &str,
     array: &Array,
     postfix: &str,
 ) {
+    if d.tags().is_compressed() {
+        s.wln("let mut encoder = flate2::write::ZlibEncoder::new(w, flate2::Compression::default());"); 
+    }
+
     s.open_curly(format!(
         "for i in {prefix}{name}.iter()",
-        name = variable_name,
+        name = d.name(),
         prefix = variable_prefix
     ));
 
     match array.ty() {
-        ArrayType::Integer(integer_type) => s.wln(format!(
-            "w.write_all(&i.to_{endian}_bytes()){postfix}?;",
-            endian = integer_type.rust_endian_str(),
-            postfix = postfix,
-        )),
+        ArrayType::Integer(integer_type) => {
+            s.wln(format!(
+                "{writer}.write_all(&i.to_{endian}_bytes()){postfix}?;",
+                writer = if d.tags().is_compressed() {"encoder"} else {"w"},
+                endian = integer_type.rust_endian_str(),
+                postfix = postfix,
+            ))
+        },
         ArrayType::Complex(_) => s.wln("i.write_into_vec(w)?;"),
         ArrayType::CString => {
             s.wln(format!("w.write_all(i.as_bytes()){}?;", postfix));
@@ -216,7 +223,7 @@ pub(crate) fn print_write_definition(
             ));
         }
         Type::Array(array) => {
-            print_write_field_array(s, d.name(), variable_prefix, array, postfix);
+            print_write_field_array(s, d, variable_prefix, array, postfix);
         }
         Type::Enum { e, upcast } | Type::Flag { e, upcast } => {
             let integer = match upcast {
diff --git a/wow_message_parser/tests/wireshark/imports.txt b/wow_message_parser/tests/wireshark/imports.txt
index 8b6e012c1c..f4eb07395c 100644
--- a/wow_message_parser/tests/wireshark/imports.txt
+++ b/wow_message_parser/tests/wireshark/imports.txt
@@ -6,6 +6,7 @@ static int hf_woww_action_bars = -1;
 static int hf_woww_action_type = -1;
 static int hf_woww_activate_taxi_reply = -1;
 static int hf_woww_actual_roll = -1;
+static int hf_woww_addon_info = -1;
 static int hf_woww_agility = -1;
 static int hf_woww_ai_reaction = -1;
 static int hf_woww_allow_movement = -1;
@@ -161,7 +162,6 @@ static int hf_woww_client_proof = -1;
 static int hf_woww_client_seed = -1;
 static int hf_woww_code = -1;
 static int hf_woww_coded = -1;
-static int hf_woww_compressed_addon_info = -1;
 static int hf_woww_compressed_chat_data = -1;
 static int hf_woww_container_slots = -1;
 static int hf_woww_content = -1;
diff --git a/wow_message_parser/tests/wireshark/parser.txt b/wow_message_parser/tests/wireshark/parser.txt
index 01e89228e5..aedff6d74f 100644
--- a/wow_message_parser/tests/wireshark/parser.txt
+++ b/wow_message_parser/tests/wireshark/parser.txt
@@ -82,7 +82,7 @@
             ptvcursor_add(ptv, hf_woww_client_proof, 20, ENC_NA);
             ptvcursor_add(ptv, hf_woww_decompressed_addon_info_size, 4, ENC_LITTLE_ENDIAN);
             len = offset_packet_end - ptvcursor_current_offset(ptv);
-            ptvcursor_add(ptv, hf_woww_compressed_addon_info, len, ENC_NA);
+            ptvcursor_add(ptv, hf_woww_addon_info, len, ENC_NA);
             break;
         case CMSG_AUTOBANK_ITEM:
             ptvcursor_add(ptv, hf_woww_bag_index, 1, ENC_LITTLE_ENDIAN);
diff --git a/wow_message_parser/tests/wireshark/register.txt b/wow_message_parser/tests/wireshark/register.txt
index c41f22727b..8232a2864f 100644
--- a/wow_message_parser/tests/wireshark/register.txt
+++ b/wow_message_parser/tests/wireshark/register.txt
@@ -46,6 +46,12 @@
                 NULL, HFILL
             }
         },
+        { &hf_woww_addon_info,
+            { "Addon Info", "woww.addon.info",
+                FT_BYTES, BASE_NONE, NULL, 0,
+                NULL, HFILL
+            }
+        },
         { &hf_woww_agility,
             { "Agility", "woww.agility",
                 FT_UINT32, BASE_HEX_DEC, NULL, 0,
@@ -976,12 +982,6 @@
                 NULL, HFILL
             }
         },
-        { &hf_woww_compressed_addon_info,
-            { "Compressed Addon Info", "woww.compressed.addon.info",
-                FT_BYTES, BASE_NONE, NULL, 0,
-                NULL, HFILL
-            }
-        },
         { &hf_woww_compressed_chat_data,
             { "Compressed Chat Data", "woww.compressed.chat.data",
                 FT_BYTES, BASE_NONE, NULL, 0,
diff --git a/wow_message_parser/wowm/world/character_screen/cmsg_auth_session.wowm b/wow_message_parser/wowm/world/character_screen/cmsg_auth_session.wowm
index f3d6a93bad..1bcd0c1920 100644
--- a/wow_message_parser/wowm/world/character_screen/cmsg_auth_session.wowm
+++ b/wow_message_parser/wowm/world/character_screen/cmsg_auth_session.wowm
@@ -7,8 +7,8 @@ cmsg CMSG_AUTH_SESSION = 0x1ED {
     u32 client_seed;
     u8[20] client_proof;
     u32 decompressed_addon_info_size;
-    u8[-] compressed_addon_info {
-        compressed = "true";
+    u8[-] addon_info {
+        compressed = "decompressed_addon_info_size";
     }
 } {
     description = "Sent after receiving [SMSG_AUTH_CHALLENGE].";
@@ -26,14 +26,45 @@ test CMSG_AUTH_SESSION {
         219, 164, 251, 163, 231, 126, 103, 172, 234, 198,
     ];
     decompressed_addon_info_size = 342;
-    compressed_addon_info = [
-        120, 156, 117, 204, 189, 14, 194, 48, 12, 4, 224, 242, 30, 188, 12, 97, 64, 149, 200, 66, 195, 140, 76,
-        226, 34, 11, 199, 169, 140, 203, 79, 159, 30, 22, 36, 6, 115, 235, 119, 119, 129, 105, 89, 64, 203,
-        105, 51, 103, 163, 38, 199, 190, 91, 213, 199, 122, 223, 125, 18, 190, 22, 192, 140, 113, 36,
-        228, 18, 73, 168, 194, 228, 149, 72, 10, 201, 197, 61, 216, 182, 122, 6, 75, 248, 52, 15, 21,
-        70, 115, 103, 187, 56, 204, 122, 199, 151, 139, 189, 220, 38, 204, 254, 48, 66, 214, 230, 202,
-        1, 168, 184, 144, 128, 81, 252, 183, 164, 80, 112, 184, 18, 243, 63, 38, 65, 253, 181, 55, 144,
-        25, 102, 143,
+    addon_info = [
+        0x42, 0x6c, 0x69, 0x7a, 0x7a, 0x61, 0x72, 0x64, 0x5f,
+        0x41, 0x75, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x55, 0x49,
+        0x00, 0x01, 0x6d, 0x77, 0x1c, 0x4c, 0x00, 0x00, 0x00,
+        0x00, 0x42, 0x6c, 0x69, 0x7a, 0x7a, 0x61, 0x72, 0x64,
+        0x5f, 0x42, 0x61, 0x74, 0x74, 0x6c, 0x65, 0x66, 0x69,
+        0x65, 0x6c, 0x64, 0x4d, 0x69, 0x6e, 0x69, 0x6d, 0x61,
+        0x70, 0x00, 0x01, 0x6d, 0x77, 0x1c, 0x4c, 0x00, 0x00,
+        0x00, 0x00, 0x42, 0x6c, 0x69, 0x7a, 0x7a, 0x61, 0x72,
+        0x64, 0x5f, 0x42, 0x69, 0x6e, 0x64, 0x69, 0x6e, 0x67,
+        0x55, 0x49, 0x00, 0x01, 0x6d, 0x77, 0x1c, 0x4c, 0x00,
+        0x00, 0x00, 0x00, 0x42, 0x6c, 0x69, 0x7a, 0x7a, 0x61,
+        0x72, 0x64, 0x5f, 0x43, 0x6f, 0x6d, 0x62, 0x61, 0x74,
+        0x54, 0x65, 0x78, 0x74, 0x00, 0x01, 0x6d, 0x77, 0x1c,
+        0x4c, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6c, 0x69, 0x7a,
+        0x7a, 0x61, 0x72, 0x64, 0x5f, 0x43, 0x72, 0x61, 0x66,
+        0x74, 0x55, 0x49, 0x00, 0x01, 0x6d, 0x77, 0x1c, 0x4c,
+        0x00, 0x00, 0x00, 0x00, 0x42, 0x6c, 0x69, 0x7a, 0x7a,
+        0x61, 0x72, 0x64, 0x5f, 0x47, 0x4d, 0x53, 0x75, 0x72,
+        0x76, 0x65, 0x79, 0x55, 0x49, 0x00, 0x01, 0x6d, 0x77,
+        0x1c, 0x4c, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6c, 0x69,
+        0x7a, 0x7a, 0x61, 0x72, 0x64, 0x5f, 0x49, 0x6e, 0x73,
+        0x70, 0x65, 0x63, 0x74, 0x55, 0x49, 0x00, 0x01, 0x6d,
+        0x77, 0x1c, 0x4c, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6c,
+        0x69, 0x7a, 0x7a, 0x61, 0x72, 0x64, 0x5f, 0x4d, 0x61,
+        0x63, 0x72, 0x6f, 0x55, 0x49, 0x00, 0x01, 0x6d, 0x77,
+        0x1c, 0x4c, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6c, 0x69,
+        0x7a, 0x7a, 0x61, 0x72, 0x64, 0x5f, 0x52, 0x61, 0x69,
+        0x64, 0x55, 0x49, 0x00, 0x01, 0x6d, 0x77, 0x1c, 0x4c,
+        0x00, 0x00, 0x00, 0x00, 0x42, 0x6c, 0x69, 0x7a, 0x7a,
+        0x61, 0x72, 0x64, 0x5f, 0x54, 0x61, 0x6c, 0x65, 0x6e,
+        0x74, 0x55, 0x49, 0x00, 0x01, 0x6d, 0x77, 0x1c, 0x4c,
+        0x00, 0x00, 0x00, 0x00, 0x42, 0x6c, 0x69, 0x7a, 0x7a,
+        0x61, 0x72, 0x64, 0x5f, 0x54, 0x72, 0x61, 0x64, 0x65,
+        0x53, 0x6b, 0x69, 0x6c, 0x6c, 0x55, 0x49, 0x00, 0x01,
+        0x6d, 0x77, 0x1c, 0x4c, 0x00, 0x00, 0x00, 0x00, 0x42,
+        0x6c, 0x69, 0x7a, 0x7a, 0x61, 0x72, 0x64, 0x5f, 0x54,
+        0x72, 0x61, 0x69, 0x6e, 0x65, 0x72, 0x55, 0x49, 0x00,
+        0x01, 0x6d, 0x77, 0x1c, 0x4c, 0x00, 0x00, 0x00, 0x00
     ];
 } [
   0x00, 0xac, /* size */
@@ -82,7 +113,9 @@ cmsg CMSG_AUTH_SESSION = 0x1ED {
     }
     u8[20] client_proof;
     u32 decompressed_addon_info_size;
-    u8[-] compressed_addon_info;
+    u8[-] addon_info  {
+        compressed = "decompressed_addon_info_size";
+    }
 } {
     description = "Sent after receiving [SMSG_AUTH_CHALLENGE].";
     comment = "This message is never encrypted.";
diff --git a/wow_world_messages/Cargo.toml b/wow_world_messages/Cargo.toml
index eda4e174dc..6042fe80cf 100644
--- a/wow_world_messages/Cargo.toml
+++ b/wow_world_messages/Cargo.toml
@@ -26,6 +26,10 @@ encryption = ["wow_srp"]
 version = "0.4"
 optional = true
 
+[dependencies.flate2]
+version = "1.0.24"
+optional = false
+
 [dependencies.tokio]
 version = "1"
 default-features = false
diff --git a/wow_world_messages/src/util/mod.rs b/wow_world_messages/src/util/mod.rs
index f03dfe7214..c8f61217bd 100644
--- a/wow_world_messages/src/util/mod.rs
+++ b/wow_world_messages/src/util/mod.rs
@@ -174,3 +174,10 @@ pub fn read_f64_be<R: Read>(r: &mut R) -> Result<f64, std::io::Error> {
     r.read_exact(&mut v)?;
     Ok(f64::from_be_bytes(v))
 }
+
+pub fn zlib_compressed_size(data: &[u8]) -> usize {
+    let mut encoder = flate2::write::ZlibEncoder::new(Vec::new(), flate2::Compression::default());
+    encoder.write_all(data).expect("Failed to compress data when calculating message size.");
+    let compressed_data = encoder.finish().expect("Failed to flush compressed data when calculating message size.");
+    compressed_data.len()
+}
diff --git a/wow_world_messages/src/world/shared/cmsg_auth_session12.rs b/wow_world_messages/src/world/shared/cmsg_auth_session12.rs
index f33acb292e..3f2545ebb0 100644
--- a/wow_world_messages/src/world/shared/cmsg_auth_session12.rs
+++ b/wow_world_messages/src/world/shared/cmsg_auth_session12.rs
@@ -15,7 +15,7 @@ use std::io::{Write, Read};
 ///     u32 client_seed;
 ///     u8[20] client_proof;
 ///     u32 decompressed_addon_info_size;
-///     u8[-] compressed_addon_info;
+///     u8[-] addon_info;
 /// }
 /// ```
 pub struct CMSG_AUTH_SESSION {
@@ -27,7 +27,7 @@ pub struct CMSG_AUTH_SESSION {
     pub client_seed: u32,
     pub client_proof: [u8; 20],
     pub decompressed_addon_info_size: u32,
-    pub compressed_addon_info: Vec<u8>,
+    pub addon_info: Vec<u8>,
 }
 
 impl crate::Message for CMSG_AUTH_SESSION {
@@ -62,9 +62,10 @@ impl crate::Message for CMSG_AUTH_SESSION {
         // decompressed_addon_info_size: u32
         w.write_all(&self.decompressed_addon_info_size.to_le_bytes())?;
 
-        // compressed_addon_info: u8[-]
-        for i in self.compressed_addon_info.iter() {
-            w.write_all(&i.to_le_bytes())?;
+        // addon_info: u8[-]
+        let mut encoder = flate2::write::ZlibEncoder::new(w, flate2::Compression::default());
+        for i in self.addon_info.iter() {
+            encoder.write_all(&i.to_le_bytes())?;
         }
 
         Ok(())
@@ -90,7 +91,7 @@ impl crate::Message for CMSG_AUTH_SESSION {
         // decompressed_addon_info_size: u32
         let decompressed_addon_info_size = crate::util::read_u32_le(r)?;
 
-        // compressed_addon_info: u8[-]
+        // addon_info: u8[-]
         let mut current_size = {
             4 // build: u32
             + 4 // server_id: u32
@@ -99,12 +100,18 @@ impl crate::Message for CMSG_AUTH_SESSION {
             + 20 * core::mem::size_of::<u8>() // client_proof: u8[20]
             + 4 // decompressed_addon_info_size: u32
         };
-        let mut compressed_addon_info = Vec::with_capacity(body_size as usize - current_size);
+        let mut addon_info = Vec::with_capacity(body_size as usize - current_size);
         while current_size < (body_size as usize) {
-            compressed_addon_info.push(crate::util::read_u8_le(r)?);
+            addon_info.push(crate::util::read_u8_le(r)?);
             current_size += 1;
         }
 
+        let mut addon_info_temp = Vec::with_capacity(decompressed_addon_info_size as usize);
+        let mut decoder = flate2::read::ZlibDecoder::new(addon_info.as_slice());
+        decoder.read_to_end(&mut addon_info_temp)?;
+
+        let mut addon_info = addon_info_temp;
+
         Ok(Self {
             build,
             server_id,
@@ -112,7 +119,7 @@ impl crate::Message for CMSG_AUTH_SESSION {
             client_seed,
             client_proof,
             decompressed_addon_info_size,
-            compressed_addon_info,
+            addon_info,
         })
     }
 
@@ -131,7 +138,7 @@ impl CMSG_AUTH_SESSION {
         + 4 // client_seed: u32
         + 20 * core::mem::size_of::<u8>() // client_proof: u8[20]
         + 4 // decompressed_addon_info_size: u32
-        + self.compressed_addon_info.len() * core::mem::size_of::<u8>() // compressed_addon_info: u8[-]
+        + crate::util::zlib_compressed_size(&self.addon_info) // addon_info: u8[-]
     }
 }
 
@@ -171,19 +178,38 @@ mod test1 {
             client_proof: [ 0x88, 0x9D, 0xEF, 0x05, 0x25, 0xBB, 0xC1, 0xAB, 0xA7,
                  0x8A, 0xDB, 0xA4, 0xFB, 0xA3, 0xE7, 0x7E, 0x67, 0xAC, 0xEA, 0xC6, ],
             decompressed_addon_info_size: 0x156,
-            compressed_addon_info: vec![ 0x78, 0x9C, 0x75, 0xCC, 0xBD, 0x0E, 0xC2,
-                 0x30, 0x0C, 0x04, 0xE0, 0xF2, 0x1E, 0xBC, 0x0C, 0x61, 0x40, 0x95,
-                 0xC8, 0x42, 0xC3, 0x8C, 0x4C, 0xE2, 0x22, 0x0B, 0xC7, 0xA9, 0x8C,
-                 0xCB, 0x4F, 0x9F, 0x1E, 0x16, 0x24, 0x06, 0x73, 0xEB, 0x77, 0x77,
-                 0x81, 0x69, 0x59, 0x40, 0xCB, 0x69, 0x33, 0x67, 0xA3, 0x26, 0xC7,
-                 0xBE, 0x5B, 0xD5, 0xC7, 0x7A, 0xDF, 0x7D, 0x12, 0xBE, 0x16, 0xC0,
-                 0x8C, 0x71, 0x24, 0xE4, 0x12, 0x49, 0xA8, 0xC2, 0xE4, 0x95, 0x48,
-                 0x0A, 0xC9, 0xC5, 0x3D, 0xD8, 0xB6, 0x7A, 0x06, 0x4B, 0xF8, 0x34,
-                 0x0F, 0x15, 0x46, 0x73, 0x67, 0xBB, 0x38, 0xCC, 0x7A, 0xC7, 0x97,
-                 0x8B, 0xBD, 0xDC, 0x26, 0xCC, 0xFE, 0x30, 0x42, 0xD6, 0xE6, 0xCA,
-                 0x01, 0xA8, 0xB8, 0x90, 0x80, 0x51, 0xFC, 0xB7, 0xA4, 0x50, 0x70,
-                 0xB8, 0x12, 0xF3, 0x3F, 0x26, 0x41, 0xFD, 0xB5, 0x37, 0x90, 0x19,
-                 0x66, 0x8F, ],
+            addon_info: vec![ 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F,
+                 0x41, 0x75, 0x63, 0x74, 0x69, 0x6F, 0x6E, 0x55, 0x49, 0x00, 0x01,
+                 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69,
+                 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x42, 0x61, 0x74, 0x74, 0x6C,
+                 0x65, 0x66, 0x69, 0x65, 0x6C, 0x64, 0x4D, 0x69, 0x6E, 0x69, 0x6D,
+                 0x61, 0x70, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00,
+                 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x42,
+                 0x69, 0x6E, 0x64, 0x69, 0x6E, 0x67, 0x55, 0x49, 0x00, 0x01, 0x6D,
+                 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A,
+                 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x43, 0x6F, 0x6D, 0x62, 0x61, 0x74,
+                 0x54, 0x65, 0x78, 0x74, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00,
+                 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64,
+                 0x5F, 0x43, 0x72, 0x61, 0x66, 0x74, 0x55, 0x49, 0x00, 0x01, 0x6D,
+                 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A,
+                 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x47, 0x4D, 0x53, 0x75, 0x72, 0x76,
+                 0x65, 0x79, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00,
+                 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64,
+                 0x5F, 0x49, 0x6E, 0x73, 0x70, 0x65, 0x63, 0x74, 0x55, 0x49, 0x00,
+                 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C,
+                 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x4D, 0x61, 0x63, 0x72,
+                 0x6F, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00,
+                 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F,
+                 0x52, 0x61, 0x69, 0x64, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C,
+                 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61,
+                 0x72, 0x64, 0x5F, 0x54, 0x61, 0x6C, 0x65, 0x6E, 0x74, 0x55, 0x49,
+                 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42,
+                 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x54, 0x72, 0x61,
+                 0x64, 0x65, 0x53, 0x6B, 0x69, 0x6C, 0x6C, 0x55, 0x49, 0x00, 0x01,
+                 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69,
+                 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x54, 0x72, 0x61, 0x69, 0x6E,
+                 0x65, 0x72, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00,
+                 0x00, 0x00, 0x00, ],
         };
 
         let header_size = 2 + 4;
@@ -199,7 +225,7 @@ mod test1 {
         assert_eq!(t.client_seed, expected.client_seed);
         assert_eq!(t.client_proof, expected.client_proof);
         assert_eq!(t.decompressed_addon_info_size, expected.decompressed_addon_info_size);
-        assert_eq!(t.compressed_addon_info, expected.compressed_addon_info);
+        assert_eq!(t.addon_info, expected.addon_info);
 
         assert_eq!(t.size() + header_size, RAW0.len());
 
@@ -221,19 +247,38 @@ mod test1 {
             client_proof: [ 0x88, 0x9D, 0xEF, 0x05, 0x25, 0xBB, 0xC1, 0xAB, 0xA7,
                  0x8A, 0xDB, 0xA4, 0xFB, 0xA3, 0xE7, 0x7E, 0x67, 0xAC, 0xEA, 0xC6, ],
             decompressed_addon_info_size: 0x156,
-            compressed_addon_info: vec![ 0x78, 0x9C, 0x75, 0xCC, 0xBD, 0x0E, 0xC2,
-                 0x30, 0x0C, 0x04, 0xE0, 0xF2, 0x1E, 0xBC, 0x0C, 0x61, 0x40, 0x95,
-                 0xC8, 0x42, 0xC3, 0x8C, 0x4C, 0xE2, 0x22, 0x0B, 0xC7, 0xA9, 0x8C,
-                 0xCB, 0x4F, 0x9F, 0x1E, 0x16, 0x24, 0x06, 0x73, 0xEB, 0x77, 0x77,
-                 0x81, 0x69, 0x59, 0x40, 0xCB, 0x69, 0x33, 0x67, 0xA3, 0x26, 0xC7,
-                 0xBE, 0x5B, 0xD5, 0xC7, 0x7A, 0xDF, 0x7D, 0x12, 0xBE, 0x16, 0xC0,
-                 0x8C, 0x71, 0x24, 0xE4, 0x12, 0x49, 0xA8, 0xC2, 0xE4, 0x95, 0x48,
-                 0x0A, 0xC9, 0xC5, 0x3D, 0xD8, 0xB6, 0x7A, 0x06, 0x4B, 0xF8, 0x34,
-                 0x0F, 0x15, 0x46, 0x73, 0x67, 0xBB, 0x38, 0xCC, 0x7A, 0xC7, 0x97,
-                 0x8B, 0xBD, 0xDC, 0x26, 0xCC, 0xFE, 0x30, 0x42, 0xD6, 0xE6, 0xCA,
-                 0x01, 0xA8, 0xB8, 0x90, 0x80, 0x51, 0xFC, 0xB7, 0xA4, 0x50, 0x70,
-                 0xB8, 0x12, 0xF3, 0x3F, 0x26, 0x41, 0xFD, 0xB5, 0x37, 0x90, 0x19,
-                 0x66, 0x8F, ],
+            addon_info: vec![ 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F,
+                 0x41, 0x75, 0x63, 0x74, 0x69, 0x6F, 0x6E, 0x55, 0x49, 0x00, 0x01,
+                 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69,
+                 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x42, 0x61, 0x74, 0x74, 0x6C,
+                 0x65, 0x66, 0x69, 0x65, 0x6C, 0x64, 0x4D, 0x69, 0x6E, 0x69, 0x6D,
+                 0x61, 0x70, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00,
+                 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x42,
+                 0x69, 0x6E, 0x64, 0x69, 0x6E, 0x67, 0x55, 0x49, 0x00, 0x01, 0x6D,
+                 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A,
+                 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x43, 0x6F, 0x6D, 0x62, 0x61, 0x74,
+                 0x54, 0x65, 0x78, 0x74, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00,
+                 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64,
+                 0x5F, 0x43, 0x72, 0x61, 0x66, 0x74, 0x55, 0x49, 0x00, 0x01, 0x6D,
+                 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A,
+                 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x47, 0x4D, 0x53, 0x75, 0x72, 0x76,
+                 0x65, 0x79, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00,
+                 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64,
+                 0x5F, 0x49, 0x6E, 0x73, 0x70, 0x65, 0x63, 0x74, 0x55, 0x49, 0x00,
+                 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C,
+                 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x4D, 0x61, 0x63, 0x72,
+                 0x6F, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00,
+                 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F,
+                 0x52, 0x61, 0x69, 0x64, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C,
+                 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61,
+                 0x72, 0x64, 0x5F, 0x54, 0x61, 0x6C, 0x65, 0x6E, 0x74, 0x55, 0x49,
+                 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42,
+                 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x54, 0x72, 0x61,
+                 0x64, 0x65, 0x53, 0x6B, 0x69, 0x6C, 0x6C, 0x55, 0x49, 0x00, 0x01,
+                 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69,
+                 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x54, 0x72, 0x61, 0x69, 0x6E,
+                 0x65, 0x72, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00,
+                 0x00, 0x00, 0x00, ],
         };
 
         let header_size = 2 + 4;
@@ -249,7 +294,7 @@ mod test1 {
         assert_eq!(t.client_seed, expected.client_seed);
         assert_eq!(t.client_proof, expected.client_proof);
         assert_eq!(t.decompressed_addon_info_size, expected.decompressed_addon_info_size);
-        assert_eq!(t.compressed_addon_info, expected.compressed_addon_info);
+        assert_eq!(t.addon_info, expected.addon_info);
 
         assert_eq!(t.size() + header_size, RAW0.len());
 
@@ -271,19 +316,38 @@ mod test1 {
             client_proof: [ 0x88, 0x9D, 0xEF, 0x05, 0x25, 0xBB, 0xC1, 0xAB, 0xA7,
                  0x8A, 0xDB, 0xA4, 0xFB, 0xA3, 0xE7, 0x7E, 0x67, 0xAC, 0xEA, 0xC6, ],
             decompressed_addon_info_size: 0x156,
-            compressed_addon_info: vec![ 0x78, 0x9C, 0x75, 0xCC, 0xBD, 0x0E, 0xC2,
-                 0x30, 0x0C, 0x04, 0xE0, 0xF2, 0x1E, 0xBC, 0x0C, 0x61, 0x40, 0x95,
-                 0xC8, 0x42, 0xC3, 0x8C, 0x4C, 0xE2, 0x22, 0x0B, 0xC7, 0xA9, 0x8C,
-                 0xCB, 0x4F, 0x9F, 0x1E, 0x16, 0x24, 0x06, 0x73, 0xEB, 0x77, 0x77,
-                 0x81, 0x69, 0x59, 0x40, 0xCB, 0x69, 0x33, 0x67, 0xA3, 0x26, 0xC7,
-                 0xBE, 0x5B, 0xD5, 0xC7, 0x7A, 0xDF, 0x7D, 0x12, 0xBE, 0x16, 0xC0,
-                 0x8C, 0x71, 0x24, 0xE4, 0x12, 0x49, 0xA8, 0xC2, 0xE4, 0x95, 0x48,
-                 0x0A, 0xC9, 0xC5, 0x3D, 0xD8, 0xB6, 0x7A, 0x06, 0x4B, 0xF8, 0x34,
-                 0x0F, 0x15, 0x46, 0x73, 0x67, 0xBB, 0x38, 0xCC, 0x7A, 0xC7, 0x97,
-                 0x8B, 0xBD, 0xDC, 0x26, 0xCC, 0xFE, 0x30, 0x42, 0xD6, 0xE6, 0xCA,
-                 0x01, 0xA8, 0xB8, 0x90, 0x80, 0x51, 0xFC, 0xB7, 0xA4, 0x50, 0x70,
-                 0xB8, 0x12, 0xF3, 0x3F, 0x26, 0x41, 0xFD, 0xB5, 0x37, 0x90, 0x19,
-                 0x66, 0x8F, ],
+            addon_info: vec![ 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F,
+                 0x41, 0x75, 0x63, 0x74, 0x69, 0x6F, 0x6E, 0x55, 0x49, 0x00, 0x01,
+                 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69,
+                 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x42, 0x61, 0x74, 0x74, 0x6C,
+                 0x65, 0x66, 0x69, 0x65, 0x6C, 0x64, 0x4D, 0x69, 0x6E, 0x69, 0x6D,
+                 0x61, 0x70, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00,
+                 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x42,
+                 0x69, 0x6E, 0x64, 0x69, 0x6E, 0x67, 0x55, 0x49, 0x00, 0x01, 0x6D,
+                 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A,
+                 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x43, 0x6F, 0x6D, 0x62, 0x61, 0x74,
+                 0x54, 0x65, 0x78, 0x74, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00,
+                 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64,
+                 0x5F, 0x43, 0x72, 0x61, 0x66, 0x74, 0x55, 0x49, 0x00, 0x01, 0x6D,
+                 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A,
+                 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x47, 0x4D, 0x53, 0x75, 0x72, 0x76,
+                 0x65, 0x79, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00,
+                 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64,
+                 0x5F, 0x49, 0x6E, 0x73, 0x70, 0x65, 0x63, 0x74, 0x55, 0x49, 0x00,
+                 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C,
+                 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x4D, 0x61, 0x63, 0x72,
+                 0x6F, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00,
+                 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F,
+                 0x52, 0x61, 0x69, 0x64, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C,
+                 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61,
+                 0x72, 0x64, 0x5F, 0x54, 0x61, 0x6C, 0x65, 0x6E, 0x74, 0x55, 0x49,
+                 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42,
+                 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x54, 0x72, 0x61,
+                 0x64, 0x65, 0x53, 0x6B, 0x69, 0x6C, 0x6C, 0x55, 0x49, 0x00, 0x01,
+                 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69,
+                 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x54, 0x72, 0x61, 0x69, 0x6E,
+                 0x65, 0x72, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00,
+                 0x00, 0x00, 0x00, ],
         };
 
         let header_size = 2 + 4;
@@ -299,7 +363,7 @@ mod test1 {
         assert_eq!(t.client_seed, expected.client_seed);
         assert_eq!(t.client_proof, expected.client_proof);
         assert_eq!(t.decompressed_addon_info_size, expected.decompressed_addon_info_size);
-        assert_eq!(t.compressed_addon_info, expected.compressed_addon_info);
+        assert_eq!(t.addon_info, expected.addon_info);
 
         assert_eq!(t.size() + header_size, RAW0.len());
 
@@ -347,19 +411,38 @@ mod test2 {
             client_proof: [ 0x88, 0x9D, 0xEF, 0x05, 0x25, 0xBB, 0xC1, 0xAB, 0xA7,
                  0x8A, 0xDB, 0xA4, 0xFB, 0xA3, 0xE7, 0x7E, 0x67, 0xAC, 0xEA, 0xC6, ],
             decompressed_addon_info_size: 0x156,
-            compressed_addon_info: vec![ 0x78, 0x9C, 0x75, 0xCC, 0xBD, 0x0E, 0xC2,
-                 0x30, 0x0C, 0x04, 0xE0, 0xF2, 0x1E, 0xBC, 0x0C, 0x61, 0x40, 0x95,
-                 0xC8, 0x42, 0xC3, 0x8C, 0x4C, 0xE2, 0x22, 0x0B, 0xC7, 0xA9, 0x8C,
-                 0xCB, 0x4F, 0x9F, 0x1E, 0x16, 0x24, 0x06, 0x73, 0xEB, 0x77, 0x77,
-                 0x81, 0x69, 0x59, 0x40, 0xCB, 0x69, 0x33, 0x67, 0xA3, 0x26, 0xC7,
-                 0xBE, 0x5B, 0xD5, 0xC7, 0x7A, 0xDF, 0x7D, 0x12, 0xBE, 0x16, 0xC0,
-                 0x8C, 0x71, 0x24, 0xE4, 0x12, 0x49, 0xA8, 0xC2, 0xE4, 0x95, 0x48,
-                 0x0A, 0xC9, 0xC5, 0x3D, 0xD8, 0xB6, 0x7A, 0x06, 0x4B, 0xF8, 0x34,
-                 0x0F, 0x15, 0x46, 0x73, 0x67, 0xBB, 0x38, 0xCC, 0x7A, 0xC7, 0x97,
-                 0x8B, 0xBD, 0xDC, 0x26, 0xCC, 0xFE, 0x30, 0x42, 0xD6, 0xE6, 0xCA,
-                 0x01, 0xA8, 0xB8, 0x90, 0x80, 0x51, 0xFC, 0xB7, 0xA4, 0x50, 0x70,
-                 0xB8, 0x12, 0xF3, 0x3F, 0x26, 0x41, 0xFD, 0xB5, 0x37, 0x90, 0x19,
-                 0x66, 0x8F, ],
+            addon_info: vec![ 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F,
+                 0x41, 0x75, 0x63, 0x74, 0x69, 0x6F, 0x6E, 0x55, 0x49, 0x00, 0x01,
+                 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69,
+                 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x42, 0x61, 0x74, 0x74, 0x6C,
+                 0x65, 0x66, 0x69, 0x65, 0x6C, 0x64, 0x4D, 0x69, 0x6E, 0x69, 0x6D,
+                 0x61, 0x70, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00,
+                 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x42,
+                 0x69, 0x6E, 0x64, 0x69, 0x6E, 0x67, 0x55, 0x49, 0x00, 0x01, 0x6D,
+                 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A,
+                 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x43, 0x6F, 0x6D, 0x62, 0x61, 0x74,
+                 0x54, 0x65, 0x78, 0x74, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00,
+                 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64,
+                 0x5F, 0x43, 0x72, 0x61, 0x66, 0x74, 0x55, 0x49, 0x00, 0x01, 0x6D,
+                 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A,
+                 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x47, 0x4D, 0x53, 0x75, 0x72, 0x76,
+                 0x65, 0x79, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00,
+                 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64,
+                 0x5F, 0x49, 0x6E, 0x73, 0x70, 0x65, 0x63, 0x74, 0x55, 0x49, 0x00,
+                 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C,
+                 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x4D, 0x61, 0x63, 0x72,
+                 0x6F, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00,
+                 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F,
+                 0x52, 0x61, 0x69, 0x64, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C,
+                 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61,
+                 0x72, 0x64, 0x5F, 0x54, 0x61, 0x6C, 0x65, 0x6E, 0x74, 0x55, 0x49,
+                 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42,
+                 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x54, 0x72, 0x61,
+                 0x64, 0x65, 0x53, 0x6B, 0x69, 0x6C, 0x6C, 0x55, 0x49, 0x00, 0x01,
+                 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69,
+                 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x54, 0x72, 0x61, 0x69, 0x6E,
+                 0x65, 0x72, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00,
+                 0x00, 0x00, 0x00, ],
         };
 
         let header_size = 2 + 4;
@@ -375,7 +458,7 @@ mod test2 {
         assert_eq!(t.client_seed, expected.client_seed);
         assert_eq!(t.client_proof, expected.client_proof);
         assert_eq!(t.decompressed_addon_info_size, expected.decompressed_addon_info_size);
-        assert_eq!(t.compressed_addon_info, expected.compressed_addon_info);
+        assert_eq!(t.addon_info, expected.addon_info);
 
         assert_eq!(t.size() + header_size, RAW0.len());
 
@@ -397,19 +480,38 @@ mod test2 {
             client_proof: [ 0x88, 0x9D, 0xEF, 0x05, 0x25, 0xBB, 0xC1, 0xAB, 0xA7,
                  0x8A, 0xDB, 0xA4, 0xFB, 0xA3, 0xE7, 0x7E, 0x67, 0xAC, 0xEA, 0xC6, ],
             decompressed_addon_info_size: 0x156,
-            compressed_addon_info: vec![ 0x78, 0x9C, 0x75, 0xCC, 0xBD, 0x0E, 0xC2,
-                 0x30, 0x0C, 0x04, 0xE0, 0xF2, 0x1E, 0xBC, 0x0C, 0x61, 0x40, 0x95,
-                 0xC8, 0x42, 0xC3, 0x8C, 0x4C, 0xE2, 0x22, 0x0B, 0xC7, 0xA9, 0x8C,
-                 0xCB, 0x4F, 0x9F, 0x1E, 0x16, 0x24, 0x06, 0x73, 0xEB, 0x77, 0x77,
-                 0x81, 0x69, 0x59, 0x40, 0xCB, 0x69, 0x33, 0x67, 0xA3, 0x26, 0xC7,
-                 0xBE, 0x5B, 0xD5, 0xC7, 0x7A, 0xDF, 0x7D, 0x12, 0xBE, 0x16, 0xC0,
-                 0x8C, 0x71, 0x24, 0xE4, 0x12, 0x49, 0xA8, 0xC2, 0xE4, 0x95, 0x48,
-                 0x0A, 0xC9, 0xC5, 0x3D, 0xD8, 0xB6, 0x7A, 0x06, 0x4B, 0xF8, 0x34,
-                 0x0F, 0x15, 0x46, 0x73, 0x67, 0xBB, 0x38, 0xCC, 0x7A, 0xC7, 0x97,
-                 0x8B, 0xBD, 0xDC, 0x26, 0xCC, 0xFE, 0x30, 0x42, 0xD6, 0xE6, 0xCA,
-                 0x01, 0xA8, 0xB8, 0x90, 0x80, 0x51, 0xFC, 0xB7, 0xA4, 0x50, 0x70,
-                 0xB8, 0x12, 0xF3, 0x3F, 0x26, 0x41, 0xFD, 0xB5, 0x37, 0x90, 0x19,
-                 0x66, 0x8F, ],
+            addon_info: vec![ 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F,
+                 0x41, 0x75, 0x63, 0x74, 0x69, 0x6F, 0x6E, 0x55, 0x49, 0x00, 0x01,
+                 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69,
+                 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x42, 0x61, 0x74, 0x74, 0x6C,
+                 0x65, 0x66, 0x69, 0x65, 0x6C, 0x64, 0x4D, 0x69, 0x6E, 0x69, 0x6D,
+                 0x61, 0x70, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00,
+                 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x42,
+                 0x69, 0x6E, 0x64, 0x69, 0x6E, 0x67, 0x55, 0x49, 0x00, 0x01, 0x6D,
+                 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A,
+                 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x43, 0x6F, 0x6D, 0x62, 0x61, 0x74,
+                 0x54, 0x65, 0x78, 0x74, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00,
+                 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64,
+                 0x5F, 0x43, 0x72, 0x61, 0x66, 0x74, 0x55, 0x49, 0x00, 0x01, 0x6D,
+                 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A,
+                 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x47, 0x4D, 0x53, 0x75, 0x72, 0x76,
+                 0x65, 0x79, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00,
+                 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64,
+                 0x5F, 0x49, 0x6E, 0x73, 0x70, 0x65, 0x63, 0x74, 0x55, 0x49, 0x00,
+                 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C,
+                 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x4D, 0x61, 0x63, 0x72,
+                 0x6F, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00,
+                 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F,
+                 0x52, 0x61, 0x69, 0x64, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C,
+                 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61,
+                 0x72, 0x64, 0x5F, 0x54, 0x61, 0x6C, 0x65, 0x6E, 0x74, 0x55, 0x49,
+                 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42,
+                 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x54, 0x72, 0x61,
+                 0x64, 0x65, 0x53, 0x6B, 0x69, 0x6C, 0x6C, 0x55, 0x49, 0x00, 0x01,
+                 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69,
+                 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x54, 0x72, 0x61, 0x69, 0x6E,
+                 0x65, 0x72, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00,
+                 0x00, 0x00, 0x00, ],
         };
 
         let header_size = 2 + 4;
@@ -425,7 +527,7 @@ mod test2 {
         assert_eq!(t.client_seed, expected.client_seed);
         assert_eq!(t.client_proof, expected.client_proof);
         assert_eq!(t.decompressed_addon_info_size, expected.decompressed_addon_info_size);
-        assert_eq!(t.compressed_addon_info, expected.compressed_addon_info);
+        assert_eq!(t.addon_info, expected.addon_info);
 
         assert_eq!(t.size() + header_size, RAW0.len());
 
@@ -447,19 +549,38 @@ mod test2 {
             client_proof: [ 0x88, 0x9D, 0xEF, 0x05, 0x25, 0xBB, 0xC1, 0xAB, 0xA7,
                  0x8A, 0xDB, 0xA4, 0xFB, 0xA3, 0xE7, 0x7E, 0x67, 0xAC, 0xEA, 0xC6, ],
             decompressed_addon_info_size: 0x156,
-            compressed_addon_info: vec![ 0x78, 0x9C, 0x75, 0xCC, 0xBD, 0x0E, 0xC2,
-                 0x30, 0x0C, 0x04, 0xE0, 0xF2, 0x1E, 0xBC, 0x0C, 0x61, 0x40, 0x95,
-                 0xC8, 0x42, 0xC3, 0x8C, 0x4C, 0xE2, 0x22, 0x0B, 0xC7, 0xA9, 0x8C,
-                 0xCB, 0x4F, 0x9F, 0x1E, 0x16, 0x24, 0x06, 0x73, 0xEB, 0x77, 0x77,
-                 0x81, 0x69, 0x59, 0x40, 0xCB, 0x69, 0x33, 0x67, 0xA3, 0x26, 0xC7,
-                 0xBE, 0x5B, 0xD5, 0xC7, 0x7A, 0xDF, 0x7D, 0x12, 0xBE, 0x16, 0xC0,
-                 0x8C, 0x71, 0x24, 0xE4, 0x12, 0x49, 0xA8, 0xC2, 0xE4, 0x95, 0x48,
-                 0x0A, 0xC9, 0xC5, 0x3D, 0xD8, 0xB6, 0x7A, 0x06, 0x4B, 0xF8, 0x34,
-                 0x0F, 0x15, 0x46, 0x73, 0x67, 0xBB, 0x38, 0xCC, 0x7A, 0xC7, 0x97,
-                 0x8B, 0xBD, 0xDC, 0x26, 0xCC, 0xFE, 0x30, 0x42, 0xD6, 0xE6, 0xCA,
-                 0x01, 0xA8, 0xB8, 0x90, 0x80, 0x51, 0xFC, 0xB7, 0xA4, 0x50, 0x70,
-                 0xB8, 0x12, 0xF3, 0x3F, 0x26, 0x41, 0xFD, 0xB5, 0x37, 0x90, 0x19,
-                 0x66, 0x8F, ],
+            addon_info: vec![ 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F,
+                 0x41, 0x75, 0x63, 0x74, 0x69, 0x6F, 0x6E, 0x55, 0x49, 0x00, 0x01,
+                 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69,
+                 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x42, 0x61, 0x74, 0x74, 0x6C,
+                 0x65, 0x66, 0x69, 0x65, 0x6C, 0x64, 0x4D, 0x69, 0x6E, 0x69, 0x6D,
+                 0x61, 0x70, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00,
+                 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x42,
+                 0x69, 0x6E, 0x64, 0x69, 0x6E, 0x67, 0x55, 0x49, 0x00, 0x01, 0x6D,
+                 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A,
+                 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x43, 0x6F, 0x6D, 0x62, 0x61, 0x74,
+                 0x54, 0x65, 0x78, 0x74, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00,
+                 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64,
+                 0x5F, 0x43, 0x72, 0x61, 0x66, 0x74, 0x55, 0x49, 0x00, 0x01, 0x6D,
+                 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A,
+                 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x47, 0x4D, 0x53, 0x75, 0x72, 0x76,
+                 0x65, 0x79, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00,
+                 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64,
+                 0x5F, 0x49, 0x6E, 0x73, 0x70, 0x65, 0x63, 0x74, 0x55, 0x49, 0x00,
+                 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C,
+                 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x4D, 0x61, 0x63, 0x72,
+                 0x6F, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00,
+                 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F,
+                 0x52, 0x61, 0x69, 0x64, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C,
+                 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69, 0x7A, 0x7A, 0x61,
+                 0x72, 0x64, 0x5F, 0x54, 0x61, 0x6C, 0x65, 0x6E, 0x74, 0x55, 0x49,
+                 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42,
+                 0x6C, 0x69, 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x54, 0x72, 0x61,
+                 0x64, 0x65, 0x53, 0x6B, 0x69, 0x6C, 0x6C, 0x55, 0x49, 0x00, 0x01,
+                 0x6D, 0x77, 0x1C, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x42, 0x6C, 0x69,
+                 0x7A, 0x7A, 0x61, 0x72, 0x64, 0x5F, 0x54, 0x72, 0x61, 0x69, 0x6E,
+                 0x65, 0x72, 0x55, 0x49, 0x00, 0x01, 0x6D, 0x77, 0x1C, 0x4C, 0x00,
+                 0x00, 0x00, 0x00, ],
         };
 
         let header_size = 2 + 4;
@@ -475,7 +596,7 @@ mod test2 {
         assert_eq!(t.client_seed, expected.client_seed);
         assert_eq!(t.client_proof, expected.client_proof);
         assert_eq!(t.decompressed_addon_info_size, expected.decompressed_addon_info_size);
-        assert_eq!(t.compressed_addon_info, expected.compressed_addon_info);
+        assert_eq!(t.addon_info, expected.addon_info);
 
         assert_eq!(t.size() + header_size, RAW0.len());
 
diff --git a/wow_world_messages/src/world/wrath/cmsg_auth_session.rs b/wow_world_messages/src/world/wrath/cmsg_auth_session.rs
index cbec98f5c6..808e6c3de1 100644
--- a/wow_world_messages/src/world/wrath/cmsg_auth_session.rs
+++ b/wow_world_messages/src/world/wrath/cmsg_auth_session.rs
@@ -6,7 +6,7 @@ use std::io::{Write, Read};
 ///
 /// This message is never encrypted.
 ///
-/// Auto generated from the original `wowm` in file [`wow_message_parser/wowm/world/character_screen/cmsg_auth_session.wowm:70`](https://github.com/gtker/wow_messages/tree/main/wow_message_parser/wowm/world/character_screen/cmsg_auth_session.wowm#L70):
+/// Auto generated from the original `wowm` in file [`wow_message_parser/wowm/world/character_screen/cmsg_auth_session.wowm:101`](https://github.com/gtker/wow_messages/tree/main/wow_message_parser/wowm/world/character_screen/cmsg_auth_session.wowm#L101):
 /// ```text
 /// cmsg CMSG_AUTH_SESSION = 0x01ED {
 ///     u32 client_build;
@@ -20,7 +20,7 @@ use std::io::{Write, Read};
 ///     u64 dos_response;
 ///     u8[20] client_proof;
 ///     u32 decompressed_addon_info_size;
-///     u8[-] compressed_addon_info;
+///     u8[-] addon_info;
 /// }
 /// ```
 pub struct CMSG_AUTH_SESSION {
@@ -38,7 +38,7 @@ pub struct CMSG_AUTH_SESSION {
     pub dos_response: u64,
     pub client_proof: [u8; 20],
     pub decompressed_addon_info_size: u32,
-    pub compressed_addon_info: Vec<u8>,
+    pub addon_info: Vec<u8>,
 }
 
 impl crate::Message for CMSG_AUTH_SESSION {
@@ -88,9 +88,10 @@ impl crate::Message for CMSG_AUTH_SESSION {
         // decompressed_addon_info_size: u32
         w.write_all(&self.decompressed_addon_info_size.to_le_bytes())?;
 
-        // compressed_addon_info: u8[-]
-        for i in self.compressed_addon_info.iter() {
-            w.write_all(&i.to_le_bytes())?;
+        // addon_info: u8[-]
+        let mut encoder = flate2::write::ZlibEncoder::new(w, flate2::Compression::default());
+        for i in self.addon_info.iter() {
+            encoder.write_all(&i.to_le_bytes())?;
         }
 
         Ok(())
@@ -131,7 +132,7 @@ impl crate::Message for CMSG_AUTH_SESSION {
         // decompressed_addon_info_size: u32
         let decompressed_addon_info_size = crate::util::read_u32_le(r)?;
 
-        // compressed_addon_info: u8[-]
+        // addon_info: u8[-]
         let mut current_size = {
             4 // client_build: u32
             + 4 // login_server_id: u32
@@ -145,12 +146,18 @@ impl crate::Message for CMSG_AUTH_SESSION {
             + 20 * core::mem::size_of::<u8>() // client_proof: u8[20]
             + 4 // decompressed_addon_info_size: u32
         };
-        let mut compressed_addon_info = Vec::with_capacity(body_size as usize - current_size);
+        let mut addon_info = Vec::with_capacity(body_size as usize - current_size);
         while current_size < (body_size as usize) {
-            compressed_addon_info.push(crate::util::read_u8_le(r)?);
+            addon_info.push(crate::util::read_u8_le(r)?);
             current_size += 1;
         }
 
+        let mut addon_info_temp = Vec::with_capacity(decompressed_addon_info_size as usize);
+        let mut decoder = flate2::read::ZlibDecoder::new(addon_info.as_slice());
+        decoder.read_to_end(&mut addon_info_temp)?;
+
+        let mut addon_info = addon_info_temp;
+
         Ok(Self {
             client_build,
             login_server_id,
@@ -163,7 +170,7 @@ impl crate::Message for CMSG_AUTH_SESSION {
             dos_response,
             client_proof,
             decompressed_addon_info_size,
-            compressed_addon_info,
+            addon_info,
         })
     }
 
@@ -184,7 +191,7 @@ impl CMSG_AUTH_SESSION {
         + 8 // dos_response: u64
         + 20 * core::mem::size_of::<u8>() // client_proof: u8[20]
         + 4 // decompressed_addon_info_size: u32
-        + self.compressed_addon_info.len() * core::mem::size_of::<u8>() // compressed_addon_info: u8[-]
+        + crate::util::zlib_compressed_size(&self.addon_info) // addon_info: u8[-]
     }
 }
 
diff --git a/wowm_language/src/docs/cmsg_auth_session.md b/wowm_language/src/docs/cmsg_auth_session.md
index ef14ab8d49..ff6043e400 100644
--- a/wowm_language/src/docs/cmsg_auth_session.md
+++ b/wowm_language/src/docs/cmsg_auth_session.md
@@ -21,7 +21,7 @@ cmsg CMSG_AUTH_SESSION = 0x01ED {
     u32 client_seed;
     u8[20] client_proof;
     u32 decompressed_addon_info_size;
-    u8[-] compressed_addon_info;
+    u8[-] addon_info;
 }
 ```
 ### Header
@@ -45,7 +45,7 @@ CMSG have a header of 6 bytes.
 | - | 4 / Little | u32 | client_seed |  |  |
 | - | ? / - | u8[20] | client_proof |  |  |
 | - | 4 / Little | u32 | decompressed_addon_info_size |  |  |
-| - | ? / - | u8[-] | compressed_addon_info |  |  |
+| - | ? / - | u8[-] | addon_info |  |  |
 
 ### Examples
 
@@ -68,7 +68,7 @@ CMSG have a header of 6 bytes.
 10, 201, 197, 61, 216, 182, 122, 6, 75, 248, 52, 15, 21, 70, 115, 103, 187, 56, 204, 
 122, 199, 151, 139, 189, 220, 38, 204, 254, 48, 66, 214, 230, 202, 1, 168, 184, 144, 
 128, 81, 252, 183, 164, 80, 112, 184, 18, 243, 63, 38, 65, 253, 181, 55, 144, 25, 
-102, 143, // compressed_addon_info: u8[-]
+102, 143, // addon_info: u8[-]
 ```
 # CMSG_AUTH_SESSION
 
@@ -84,7 +84,7 @@ This message is never encrypted.
 
 ### Wowm Representation
 
-Autogenerated from `wowm` file at [`wow_message_parser/wowm/world/character_screen/cmsg_auth_session.wowm:70`](https://github.com/gtker/wow_messages/tree/main/wow_message_parser/wowm/world/character_screen/cmsg_auth_session.wowm#L70).
+Autogenerated from `wowm` file at [`wow_message_parser/wowm/world/character_screen/cmsg_auth_session.wowm:101`](https://github.com/gtker/wow_messages/tree/main/wow_message_parser/wowm/world/character_screen/cmsg_auth_session.wowm#L101).
 ```rust,ignore
 cmsg CMSG_AUTH_SESSION = 0x01ED {
     u32 client_build;
@@ -98,7 +98,7 @@ cmsg CMSG_AUTH_SESSION = 0x01ED {
     u64 dos_response;
     u8[20] client_proof;
     u32 decompressed_addon_info_size;
-    u8[-] compressed_addon_info;
+    u8[-] addon_info;
 }
 ```
 ### Header
@@ -127,5 +127,5 @@ CMSG have a header of 6 bytes.
 | - | 8 / Little | u64 | dos_response |  | Purpose and exact meaning of name unknown.<br/>TrinityCore has this name but never uses the variable afterwards. |
 | - | ? / - | u8[20] | client_proof |  |  |
 | - | 4 / Little | u32 | decompressed_addon_info_size |  |  |
-| - | ? / - | u8[-] | compressed_addon_info |  |  |
+| - | ? / - | u8[-] | addon_info |  |  |