Hello Arash
Glad you liked the plugin and thank you for your kind comment.
Regarding Persian numbers:
Any number that is not in English is considered an incorrect value. If the numbers are converted to Persian, then you will not be able to know if the value you entered is a Persian or English number. In order to avoid this kind of problem, the font of the numbers should not be changed.
The solar calendar is not related to the purpose of making this plugin and therefore I can not add this feature. Take a look at the internet and most likely there are plugins that will fix this problem.