diff --git a/nixos/doc/manual/release-notes/rl-2405.section.md b/nixos/doc/manual/release-notes/rl-2405.section.md
index 749ebc5cb13b..ba4d26518db8 100644
--- a/nixos/doc/manual/release-notes/rl-2405.section.md
+++ b/nixos/doc/manual/release-notes/rl-2405.section.md
@@ -38,4 +38,8 @@ In addition to numerous new and upgraded packages, this release has the followin
   existing process, but will need to start that process from gdb (so it is a
   child). Or you can set `boot.kernel.sysctl."kernel.yama.ptrace_scope"` to 0.
 
+- Gitea 1.21 upgrade has several breaking changes, including:
+  - Custom themes and other assets that were previously stored in `custom/public/*` now belong in `custom/public/assets/*`
+  - New instances of Gitea using MySQL now ignore the `[database].CHARSET` config option and always use the `utf8mb4` charset, existing instances should migrate via the `gitea doctor convert` CLI command.
+
 - The `hardware.pulseaudio` module now sets permission of pulse user home directory to 755 when running in "systemWide" mode. It fixes [issue 114399](https://github.com/NixOS/nixpkgs/issues/114399).
diff --git a/pkgs/applications/version-management/gitea/default.nix b/pkgs/applications/version-management/gitea/default.nix
index f21e58603368..5cbc4a1bd493 100644
--- a/pkgs/applications/version-management/gitea/default.nix
+++ b/pkgs/applications/version-management/gitea/default.nix
@@ -20,12 +20,12 @@
 
 buildGoModule rec {
   pname = "gitea";
-  version = "1.20.5";
+  version = "1.21.1";
 
   # not fetching directly from the git repo, because that lacks several vendor files for the web UI
   src = fetchurl {
     url = "https://dl.gitea.com/gitea/${version}/gitea-src-${version}.tar.gz";
-    hash = "sha256-cH/AHsFXOdvfSfj9AZUd3l/RlYE06o1ByZu0vvGQuXw=";
+    hash = "sha256-5WEHUMQsQNgrglS+xJ4IWHUl0a6RLLPyx0l+ECJ4R9g=";
   };
 
   vendorHash = null;