[NEED HELP] compatibility B-Mesh ver. 2.58 VS latest ver. (2.72)

Hi ! I’m new here. May I ask you for help ?

I often update using latest version of blender, but when using save-legacy, all face using bmesh and dissolve etc. is disappear. my office using 2.58 ver. (for database) but for working faster I using latest ver (2.72).

Anyone can give some advice which better working fast with bmesh & disolve without sacrifice using in ver. 2.5


oh ya, it seems when unwarp uv map, there’s alot of unproportional face…

still long journey for blender