diff --git a/utils/phpstan-watcher.sh b/utils/phpstan-watcher.sh
index d1acc906f..4c8f1bfa1 100644
--- a/utils/phpstan-watcher.sh
+++ b/utils/phpstan-watcher.sh
@@ -10,8 +10,10 @@ echo PWD: $(pwd)
 while true; do
 	inotifywait . -e close_write -r -t 300 | grep -q .php && \
 		(
+			MODIFIED=$(git ls-files -m | grep .php)
+
 			docker run --rm -v $(pwd):/app -v /tmp/phpstan-8.1:/tmp/phpstan \
-				--workdir /app php:${PHP_VERSION}-cli php -d memory_limit=-1 ./vendor/bin/phpstan --memory-limit=2G --error-format=raw
+				--workdir /app registry.fakecake.org/cthulhoo/ci-alpine:3.16 php81 -d memory_limit=-1 ./vendor/bin/phpstan --memory-limit=2G --error-format=raw analyze ${MODIFIED}
 			echo All done, RC=$?.
 		)
 	sleep 1