Yealink T46s phone delivered with FW 66.84.0.15

[nobody]

Will this FW be supported in the near Future or, do I have to downgrade the FW to the 3CX supported Version?

 

[cobaltit]

Whether or not it would supported in the future doesn't change the fact that it's not supported now. If it's too much trouble to click the one button in 3CX to downgrade feel free to run it 'as-is'. Should you have any issues you know what the first recommendation will be.