Firmware PXW-Z90_V101_E is available from Sony.

I installed it without problems, following the detailed instructions given in a pdf file.

Available here:

https://pro.sony/en_BG/support/software/pxw-z90-v1-01


Contents of update

1. Support for TLS 1.2 was added to coincide with Ustream (IBM Cloud Video)’s update from TLS 1.0/1.1 to TLS 1.2

2. Improves the shooting stability of the steady shot in high frame rate shooting.

Went smoothly, except it reset my settings. Make sure you save your camera profile. It says this in the PDF, but I wasn't paying attention:

From the PDF: After update is completed, all setup returns to the default settings set at the factory.