Hello all,
Some 2600Hz partners are having difficulty operating T4xU Yealink phones that came pre-loaded with v85 firmware. Only v84 firmware has been tested and approved for use on KAZOO and there seems to be a problem downgrading from v85 to v84. We have identified a workaround for this. You can download and manually install this firmware: http://firmwares.2600hz.com/yealink/t4x/T48U-T46U-T43U-T42U-108.85.0.27.rom
We are working on making this the default going forward without messing with existing phones that are happily running v84. This will take about 2 weeks. Once completed we will fully support the T4XU line again.