diff --git a/core/base/Dockerfile b/core/base/Dockerfile
index 2cade640..721b5db1 100644
--- a/core/base/Dockerfile
+++ b/core/base/Dockerfile
@@ -1,7 +1,7 @@
 # syntax=docker/dockerfile-upstream:1.4.3
 
 # base system image (intermediate)
-ARG DISTRO=alpine:3.14.5
+ARG DISTRO=alpine:3.16.2
 FROM $DISTRO as system
 
 ENV TZ=Etc/UTC LANG=C.UTF-8
diff --git a/core/base/libs/podop/podop/dovecot.py b/core/base/libs/podop/podop/dovecot.py
index 68bfa172..40b48eef 100644
--- a/core/base/libs/podop/podop/dovecot.py
+++ b/core/base/libs/podop/podop/dovecot.py
@@ -33,6 +33,8 @@ class DictProtocol(asyncio.Protocol):
         self.dict = None
         # Dictionary of active transaction lists per transaction id
         self.transactions = {}
+        # Dictionary of user per transaction id
+        self.transactions_user = {}
         super(DictProtocol, self).__init__()
 
     def connection_made(self, transport):
@@ -75,15 +77,15 @@ class DictProtocol(asyncio.Protocol):
         logging.debug("Client {}.{} type {}, user {}, dict {}".format(
             self.major, self.minor, self.value_type, self.user, dict_name))
 
-    async def process_lookup(self, key):
+    async def process_lookup(self, key, user=None):
         """ Process a dict lookup message
         """
-        logging.debug("Looking up {}".format(key))
+        logging.debug("Looking up {} for {}".format(key, user))
         # Priv and shared keys are handled slighlty differently
         key_type, key = key.decode("utf8").split("/", 1)
         try:
             result = await self.dict.get(
-                key, ns=(self.user if key_type == "priv" else None)
+                key, ns=((user.decode("utf8") if user else self.user) if key_type == "priv" else None)
             )
             if type(result) is str:
                 response = result.encode("utf8")
@@ -95,10 +97,11 @@ class DictProtocol(asyncio.Protocol):
         except KeyError:
             return self.reply(b"N")
 
-    def process_begin(self, transaction_id):
+    def process_begin(self, transaction_id, user=None):
         """ Process a dict begin message
         """
         self.transactions[transaction_id] = {}
+        self.transactions_user[transaction_id] = user.decode("utf8") if user else self.user
 
     def process_set(self, transaction_id, key, value):
         """ Process a dict set message
@@ -116,10 +119,11 @@ class DictProtocol(asyncio.Protocol):
             key_type, key = key.decode("utf8").split("/", 1)
             result = await self.dict.set(
                 key, json.loads(value),
-                ns=(self.user if key_type == "priv" else None)
+                ns=(self.transactions_user[transaction_id] if key_type == "priv" else None)
             )
         # Remove stored transaction
         del self.transactions[transaction_id]
+        del self.transactions_user[transaction_id]
         return self.reply(b"O", transaction_id)
 
     def reply(self, command, *args):
diff --git a/towncrier/newsfragments/2497.bugfix b/towncrier/newsfragments/2497.bugfix
new file mode 100644
index 00000000..67752060
--- /dev/null
+++ b/towncrier/newsfragments/2497.bugfix
@@ -0,0 +1 @@
+Upgrade to alpine 3.16.2