On Friday, 20 November 2020 at 16:10:40 UTC, Moshe Braner wrote:

"The firmware expiration date is not related to the aircraft specific
update cycle/date. The firmware will not expire as long as the firmware
is kept up-to-date according to the AMP. The expiry is always at least
12 months plus a few months of margin in the future when downloaded from
flarm.com."

"If the annual update cycle has expired but the firmware has not yet
expired, the device will in most cases continue to work until firmware
expiry."

"After the expiration date, the system will issue a continuous hard
warning and will not operate."

What is meant by firmware expiry date, since this is different from annual update expiry date?

Personally I don't intend to explore how my device behaves when not updated - I have it updated annually during the ARC process, although I did not know it was a requirement until I read that above from Martin Gregorie. I don't normally use the igc files from my device (igc files are uploaded by wifi from my LX9000 to SeeYou Cloud before I get out of the glider, so much more convenient), but I do extract and look at one at the start of the year to check that it is now using the latest firmware.

Incidentally, I did pay for the 2nd aerial option, and having a European device it should transmit as well as receive. I flew with that setup for two seasons before discovering that the 2nd aerial option was not active and the blade aerial on the bottom of the glider was not doing anything. The unit had been provided incorrect and was then sorted out by the UK supplier Navboys. To the best of my knowledge it now works - but I don't actually know whether it does.