diff --git a/CHANGELOG.md b/CHANGELOG.md
index afce51a..811ca79 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,12 @@
 # Changelog
 
+## [3.1.1](https://github.com/mljs/fcnnls/compare/v3.1.0...v3.1.1) (2026-07-31)
+
+
+### Performance Improvements
+
+* avoid quadratic work in the optimality check ([e3cc09c](https://github.com/mljs/fcnnls/commit/e3cc09c62aebb6becb6be7a0e24a4a04787a0d83))
+
 ## [3.1.0](https://github.com/mljs/fcnnls/compare/v3.0.0...v3.1.0) (2026-06-23)
 
 
diff --git a/package.json b/package.json
index 101be1d..61dbd04 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ml-fcnnls",
-  "version": "3.1.0",
+  "version": "3.1.1",
   "description": "Fast Combinatorial Non-negative Least Squares",
   "type": "module",
   "exports": {