diff --git a/Dockerfile.bullseye-slim b/Dockerfile.bullseye-slim
index a999e56..3a5867a 100644
--- a/Dockerfile.bullseye-slim
+++ b/Dockerfile.bullseye-slim
@@ -21,5 +21,8 @@ RUN make -Cbuild -j$(grep -c ^processor /proc/cpuinfo)
 RUN make -Cbuild install
 
 FROM debian:bullseye-slim
+RUN apt-get update && apt-get upgrade -y
+RUN apt-get install -y \
+    zlib1g-dev
 COPY --from=builder /usr/local/pvpgn /usr/local/pvpgn
 ENTRYPOINT ["/usr/local/pvpgn/sbin/bnetd", "-D"]