I recently downloaded my configurations from fota.teltonika.lt and wanted to change them in teltonika.configurator
I tried several recent versions, but each ended with an error: Failed to load selected configuration file, because 08.20.00 version with SpecId 1 is not supported.
All devices are FMC130, FW 03.27.13.Rev.54
The devices were loaded with version 8.14 config a few years ago, and have not been touched since then.
You may try to Create New Configuration on the Teltonika Configurator, then select FMC130 device, once done you have an option to select the version that you were using then Load the File so you can open that specific Configuration File.