You can mesh two or three b1300 with 3.022 firmware, i have tested before.
For example, you have 2 b1300 now, you want to mesh them. One as main router with cable, if you push and hold the mesh button, the middle light will flash with three levels. First level, it will flash slowly, which prevent you from enable mesh by accident. After few seconds, it will go to second level and flash quickly, and if you release now, it will open mesh matching. In third level it will flash more quickly and it will disable mesh after you release.
You just need to open mesh for these two device and wait, the middle light will be soild green after they were matched.