diff --git a/src/pulse/context.c b/src/pulse/context.c
index 6adfc5a95..e76950092 100644
--- a/src/pulse/context.c
+++ b/src/pulse/context.c
@@ -1369,7 +1369,7 @@ uint32_t pa_context_get_index(pa_context *c) {
     return c->client_index;
 }
 
-pa_operation *pa_context_proplist_update(pa_context *c, pa_update_mode_t mode, pa_proplist *p, pa_context_success_cb_t cb, void *userdata) {
+pa_operation *pa_context_proplist_update(pa_context *c, pa_update_mode_t mode, const pa_proplist *p, pa_context_success_cb_t cb, void *userdata) {
     pa_operation *o;
     pa_tagstruct *t;
     uint32_t tag;
diff --git a/src/pulse/context.h b/src/pulse/context.h
index 9b96f8ce5..2cb0776e5 100644
--- a/src/pulse/context.h
+++ b/src/pulse/context.h
@@ -247,7 +247,7 @@ uint32_t pa_context_get_server_protocol_version(pa_context *c);
  * initially via pa_context_new_with_proplist() as possible instead a
  * posteriori with this function, since that information may then be
  * used to route streams of the client to the right device. \since 0.9.11 */
-pa_operation *pa_context_proplist_update(pa_context *c, pa_update_mode_t mode, pa_proplist *p, pa_context_success_cb_t cb, void *userdata);
+pa_operation *pa_context_proplist_update(pa_context *c, pa_update_mode_t mode, const pa_proplist *p, pa_context_success_cb_t cb, void *userdata);
 
 /** Update the property list of the client, remove entries. \since 0.9.11 */
 pa_operation *pa_context_proplist_remove(pa_context *c, const char *const keys[], pa_context_success_cb_t cb, void *userdata);