diff --git a/nix/sources.json b/nix/sources.json
index 29748cde992..d24ae1608ac 100644
--- a/nix/sources.json
+++ b/nix/sources.json
@@ -57,10 +57,10 @@
         "homepage": null,
         "owner": "dfinity",
         "repo": "motoko-base",
-        "rev": "1b0b25399fe5747bf63321950f386ed6263456fe",
-        "sha256": "1r1y61gaqpazm1h35mz0ds4yd8imqm39pdxmpiaj5mg3sgykxdlw",
+        "rev": "40f5ecdb2b5feeb7ed5c081efd8847b218dde0aa",
+        "sha256": "0y9q2k3bc16bbn15j264hw536kvwgj1n4i2s8qsrcnz3ysvnl2fj",
         "type": "tarball",
-        "url": "https://github.com/dfinity/motoko-base/archive/1b0b25399fe5747bf63321950f386ed6263456fe.tar.gz",
+        "url": "https://github.com/dfinity/motoko-base/archive/40f5ecdb2b5feeb7ed5c081efd8847b218dde0aa.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "motoko-matchers": {