diff --git a/CHANGELOG.md b/CHANGELOG.md
index 28cbd30..a2de1ab 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,29 @@
 # Changelog
 
+## 1.0.9 (2024-05-10)
+
+* Enhancements
+  * Add `argo_limits` and `argo_varbit` for controlling the maximum number of bits supported in `HasUserFlags` (defaults to 700-bits).
+  * Add new functions to `argo_header`:
+    * `argo_header:from_http_argo_mode/1` and `argo_header:to_http_argo_mode/1`
+      * For use with HTTP header `Argo-Mode`.
+      * For example:
+        ```
+        Argo-Mode: InlineEverything;SelfDescribing;OutOfBandFieldErrors;SelfDescribingErrors;NullTerminatedStrings;NoDeduplication;HasUserFlags:10
+        ```
+    * `argo_header:from_u64/1` and `argo_header:to_u64/1`
+      * For use with encode/decode of `ArgoHeader` to an unsigned 64-bit integer.
+      * For example:
+        ```erlang
+        argo_header:from_u64(32640).
+        ```
+    * `argo_header:from_uint/1` and `argo_header:to_uint/1`
+      * For use with encode/decode of `ArgoHeader` to an unsigned integer (may be larger than 64-bits).
+      * For example:
+        ```erlang
+        argo_header:from_uint(2586086763326778769917682175246592).
+        ```
+
 ## 1.0.8 (2024-04-29)
 
 * Fixes
diff --git a/apps/argo/src/argo.app.src b/apps/argo/src/argo.app.src
index bd21732..ed7ad75 100644
--- a/apps/argo/src/argo.app.src
+++ b/apps/argo/src/argo.app.src
@@ -7,7 +7,7 @@
 %%% % @format
 {application, argo, [
     {description, "argo: Erlang implementation of Argo for GraphQL"},
-    {vsn, "1.0.8"},
+    {vsn, "1.0.9"},
     {modules, []},
     {registered, []},
     %% NOTE: Remember to sync changes to `applications` to