diff --git a/server/Dockerfile b/server/Dockerfile
index 4a58d67..9364c49 100644
--- a/server/Dockerfile
+++ b/server/Dockerfile
@@ -1,4 +1,4 @@
-FROM python:3.14.1-slim
+FROM python:3.15.0a2-slim
 
 ENV DEVPISERVER_SERVERDIR=/devpi/server
 RUN mkdir -p $DEVPISERVER_SERVERDIR && \
diff --git a/server/Dockerfile-alpine b/server/Dockerfile-alpine
index ea836fb..7e1347d 100644
--- a/server/Dockerfile-alpine
+++ b/server/Dockerfile-alpine
@@ -1,4 +1,4 @@
-FROM python:3.14.1-alpine
+FROM python:3.15.0a2-alpine
 
 ENV DEVPISERVER_SERVERDIR=/devpi/server
 RUN mkdir -p $DEVPISERVER_SERVERDIR && \