diff --git a/pika-build-config/lto.sh b/pika-build-config/lto.sh
index 6e6783a02..f0804015a 100644
--- a/pika-build-config/lto.sh
+++ b/pika-build-config/lto.sh
@@ -1,5 +1,5 @@
-export PIKA_PACKAGE_VERSION="4:24.12.0-2"
-export PIKA_PACKAGE_NAME="ktnef"
+export PIKA_PACKAGE_VERSION="3.19.1-1"
+export PIKA_PACKAGE_NAME="pyupgrade"
 export PIKA_PACKAGE_PATCH=false
 export PIKA_REBUILD=false
 export PIKA_REBUILD_VERSION="b0"