That is indeed unfortunate. I had this unit installed in 2019.
When was this released and EOL'ed ?
If Teltonika keeps model numbers but revises its hardware to the point that upgrades are not possible, this creates a confusing situation for customers. This device is offered by distributors as RUT955 w/o any version information. Therefore I may be buying, even today, an old version that cannot be upgraded.
I'll post a follow-up question on an issue with the on-board GNSS as this is my main reason for considering the upgrade.