diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8800f1ac9..4071952e6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,7 +13,15 @@ Added support for Verilog and SystemVerilog.
 ### Build
 
 CI on GitHub now uses Ubuntu 22.04 for Linux builds (previously Ubuntu
-20.04), so prebuilt binaries will require a newer glibc version to run.
+20.04), so prebuilt binaries will require a newer glibc version to
+run.
+
+### Internal
+
+Difftastic has switched from MiMalloc to Jemalloc for allocation. This
+is modest performance regression (up to 20% longer runtime in
+testing). Jemalloc is currently easier to build (see issue #805) and
+has fewer pathological performance corner cases.
 
 ## 0.63 (released 11th February 2025)