XCSoar no data No Connection Note 4, C302, K6BT

I'm not able to get data into XCSoar with my intended setup, nor with other phones I have tried. I bought a Samsung Note 4 because it has a large bright screen, I have heard others have had good luck with Note 2 and 3 and I assumed this would be even better. Are other getting a Note 4 to work?

Intended system: Note 4, Cambridge 302 vario, with a K6 team BT mux, XCS 6.7.6.

I cannot get the data connection with this setup on any android phone I tried with XCSoar.
I can get the K6 bluetooth to pair with every phone I have tried it with. I can only see a valid NMEA stream coming through on the Droid Ultra phone with the Blue GPS app.

Samsung Note 4 SM N910V Android 4.4.4 internal GPS & Baro work, K6 BT Mux data does not connect in XCSoar. [I don't know if it is relevant but there is no phone sim card or microSD data card installed. XCSoar appears to run fine from internal memory.]

Motorola Droid Ultra XT1080 Android 4.4.4 Blue GPS gets signal, NMEA stream looks good in Blue GPS. K6 BT Mux data does not connect in XCSoar.

Motorola Droid Razr Maxx Android 4.1.2, K6 BT Mux data does not connect in XCSoar.

Are there any specific settings needed for a Samsung Note 4?

What should I try next?
XCSoar 6.8 preview?
is Android 4.4 incompatible?
Would a down revision of Android? If so how what to install?
Should I try something besides K6 BT mux?
Would "blue NMEA" of any use?

could use some help.
Chris