diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index 78baf5b..0bd1b03 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "2.5.0"
+  ".": "2.5.1"
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index eca3cc8..9f6f862 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,13 @@
 
 All notable changes to the LaunchDarkly SSE Client for Ruby will be documented in this file. This project adheres to [Semantic Versioning](http://semver.org).
 
+## [2.5.1](https://github.com/launchdarkly/ruby-eventsource/compare/2.5.0...2.5.1) (2026-03-02)
+
+
+### Bug Fixes
+
+* Use in-place append for buffer concatenation to fix O(n^2) performance ([#80](https://github.com/launchdarkly/ruby-eventsource/issues/80)) ([a7e6c23](https://github.com/launchdarkly/ruby-eventsource/commit/a7e6c23835f6876d1db1a92dc479d75e8ffa0b67))
+
 ## [2.5.0](https://github.com/launchdarkly/ruby-eventsource/compare/2.4.0...2.5.0) (2026-01-23)
 
 
diff --git a/lib/ld-eventsource/version.rb b/lib/ld-eventsource/version.rb
index b91d0c5..de1fe6f 100644
--- a/lib/ld-eventsource/version.rb
+++ b/lib/ld-eventsource/version.rb
@@ -1,3 +1,3 @@
 module SSE
-  VERSION = "2.5.0" # x-release-please-version
+  VERSION = "2.5.1" # x-release-please-version
 end