diff --git a/pika-build-config/lto.sh b/pika-build-config/lto.sh
index 69298fe3d..8a56acb93 100644
--- a/pika-build-config/lto.sh
+++ b/pika-build-config/lto.sh
@@ -1,5 +1,5 @@
-export PIKA_PACKAGE_VERSION="2.8+dfsg-3"
-export PIKA_PACKAGE_NAME="gsl"
+export PIKA_PACKAGE_VERSION="5.15.13-2"
+export PIKA_PACKAGE_NAME="qtserialport-opensource-src"
 export PIKA_PACKAGE_PATCH=false
 export PIKA_REBUILD=true
 export PIKA_REBUILD_VERSION="b33"