Has there been a public release for this "beta version" ???
Yes, the Public Release was today, 11/14/16. Just click "Update Firmware" under the "Update" tab in Sentinel and you will get the update. Be sure to do the proper steps as stated during the update procedure. The 436 and 536 procedures are different.
Just curious, I downloaded 1.11.20 (Open Beta for Digital Filter Improvements 1.11.20) from the first page of this thread. Was this available by doing the update firmware in Sentinel? Or was the update available thru Sentinel 1.11.17?