diff --git a/pika-build-config/lto.sh b/pika-build-config/lto.sh
index 19c926ff6..85c89a77b 100644
--- a/pika-build-config/lto.sh
+++ b/pika-build-config/lto.sh
@@ -1,5 +1,5 @@
-export PIKA_PACKAGE_VERSION="1.0.0.10-3"
-export PIKA_PACKAGE_NAME="haskell-setlocale"
+export PIKA_PACKAGE_VERSION="1.2.1-6"
+export PIKA_PACKAGE_NAME="haskell-multimap"
 export PIKA_PACKAGE_PATCH=false
 export PIKA_REBUILD=false
 export PIKA_REBUILD_VERSION="b0"