How to identify which firmware version is newest

Take the R29 version as an example:

A:To distinguish different models.
20 means suitable for R20 devices;
23 means suitable for R23 devices;
26 means suitable for R26 devices;
27 means suitable for R27 devices;
29 means suitable for R29 devices;
110 means suitable for E10 devices;
21 means suitable for E21 devices;

B:To distinguish different OEM.
0 means the version with Akuvox logo;
1 means the version no any logo;
31 means the version support cloud, SDMC, discovery mode at the same time;
The other values are to distinguish customers with custom version demands;

C: To distinguish different branch.

D: Distinguish between different versions of the same model, the same OEM and the same branch. A higher value indicates an updated version (make sure to be under the same model, the same OEM, and the same branch);