diff --git a/koch.nim b/koch.nim
index 6b15ee6bba..fea23a1d05 100644
--- a/koch.nim
+++ b/koch.nim
@@ -16,11 +16,11 @@ const
   ChecksumsStableCommit = "5c132cd332cce5d64a0da9ac3e4c9664313dccb4" # 0.2.2
   SatStableCommit = "9d52513b3c68bfb929dbd687d4fb2836cfee6936"
 
-  NimonyStableCommit = "863a04c07277eaa0a6bb2a0059d731a59cbc09b4" # unversioned \
+  NimonyStableCommit = "f831b953d7c21d9a4b11d0042039e7f84d7c8dc9" # unversioned \
     # Note that Nimony uses Nim as a git submodule but we don't want to install
     # Nimony's dependency to Nim as we are Nim. So a `git clone` without --recursive
     # is **required** here.
-    # Commit from 2026-07-09 -- .bif files are memory mapped too
+    # Commit from 2026-07-10 -- stable .bif file format
 
   # examples of possible values for fusion: #head, #ea82b54, 1.2.3
   FusionStableHash = "#562467452b32cb7a97410ea177f083e6d8405734"