diff --git a/DOCS/client-api-changes.rst b/DOCS/client-api-changes.rst
index 1ff828339a..df2b42aa70 100644
--- a/DOCS/client-api-changes.rst
+++ b/DOCS/client-api-changes.rst
@@ -32,6 +32,12 @@ API changes
 
 ::
 
+ --- mpv 0.29.0 ---
+ 1.27   - make opengl-cb the default VO. This causes a subtle behavior change
+          if the API user called mpv_opengl_cb_init_gl(), but does not set
+          the "vo" option. Before, it would still have used another VO (like
+          on the CLI, e.g. vo=gpu). Now it'll behave as if vo=opengl-cb was
+          used.
  --- mpv 0.28.0 ---
  1.26   - remove glMPGetNativeDisplay("drm") support
         - add mpv_opengl_cb_window_pos and mpv_opengl_cb_drm_params and
diff --git a/libmpv/client.h b/libmpv/client.h
index f3e4d4c8c8..f47c670558 100644
--- a/libmpv/client.h
+++ b/libmpv/client.h
@@ -209,7 +209,7 @@ extern "C" {
  * relational operators (<, >, <=, >=).
  */
 #define MPV_MAKE_VERSION(major, minor) (((major) << 16) | (minor) | 0UL)
-#define MPV_CLIENT_API_VERSION MPV_MAKE_VERSION(1, 26)
+#define MPV_CLIENT_API_VERSION MPV_MAKE_VERSION(1, 27)
 
 /**
  * The API user is allowed to "#define MPV_ENABLE_DEPRECATED 0" before
diff --git a/video/out/vo.c b/video/out/vo.c
index c999138eee..b2aba3af7a 100644
--- a/video/out/vo.c
+++ b/video/out/vo.c
@@ -66,6 +66,9 @@ extern const struct vo_driver video_out_tct;
 
 const struct vo_driver *const video_out_drivers[] =
 {
+#if HAVE_GL
+    &video_out_opengl_cb,
+#endif
 #if HAVE_ANDROID
     &video_out_mediacodec_embed,
 #endif
@@ -103,9 +106,6 @@ const struct vo_driver *const video_out_drivers[] =
 #endif
 #if HAVE_ENCODING
     &video_out_lavc,
-#endif
-#if HAVE_GL
-    &video_out_opengl_cb,
 #endif
     NULL
 };
diff --git a/video/out/vo_opengl_cb.c b/video/out/vo_opengl_cb.c
index 4be36118a0..40dcb035ca 100644
--- a/video/out/vo_opengl_cb.c
+++ b/video/out/vo_opengl_cb.c
@@ -554,7 +554,8 @@ static int preinit(struct vo *vo)
     struct vo_priv *p = vo->priv;
     p->ctx = vo->extra.opengl_cb_context;
     if (!p->ctx) {
-        MP_FATAL(vo, "No context set.\n");
+        if (!vo->probing)
+            MP_FATAL(vo, "No context set.\n");
         return -1;
     }