diff --git a/pika-build-config/lto.sh b/pika-build-config/lto.sh
index 57bdef0f6..c737e31e1 100644
--- a/pika-build-config/lto.sh
+++ b/pika-build-config/lto.sh
@@ -1,5 +1,5 @@
-export PIKA_PACKAGE_VERSION="9.7.104-1.1"
-export PIKA_PACKAGE_NAME="irsim"
+export PIKA_PACKAGE_VERSION="4.7+ds-2"
+export PIKA_PACKAGE_NAME="mfem"
 export PIKA_PACKAGE_PATCH=false
 export PIKA_REBUILD=false
 export PIKA_REBUILD_VERSION="b0"