Good day. Thank you for your question.
Please find the reply to your questions, in the sequence below:
1) Kindly try this link - https://wiki.teltonika-gps.com/view/FMB640_firmware_errata to know the difference between firmware version 01.00.05 and 00.03.65. The changes made on FW01.00.05 are as follows:
Tachograph FrontPanel improvements
Additional tachograph parameters added
AutoCAN reading improvements
Sleep modes improvements
Battery charging/discharging improved
Tracking On-demand added
LVCAN DTC codes reading improvements
1Wire TSH202 multiple sensors support added
Periodical TSM232 SBD records saving improvements
TCP buffering to SD card added
GPRS Remote log improvements
2) The are parameters added under Tachograph (AVL ID 10501 - 10521) for FW01.00.05 and others added under FW00.03.79 such as Geofence Zone Over Speeding etc. Kindly take note that the latest firmware release version is FW01.00.13.
3) Variable type parameters are only supported by the Codec8 Extended protocol - https://wiki.teltonika-gps.com/view/Teltonika_Data_Sending_Protocols#Codec_8_Extended
4) There are no major changes to the protocol used between these versions. So it should be compatible.
Hope this information helps.