If you don’t want to wait to anybody others help and if you are a little bit familiar with it, you can change them back using totalcommander app!
.hwt is like .zip file format!
* Open theme files v2.4 & v2.5 with Totalcommander and copy "icon" pack from both files into internal SD.
* Open "icon" pack with TotalCommander" and copy/change "dynymic_icons/com.android.calender" folder from icon pack 2.4 to 2.5!
*Copy the modified folder "dynymic_icons/com.android.calender" into v2.4 "icon" pack
*Copy modified "icon2 pack into theme pack 2.5 and copy this modified theme.hwt back into folder "themes" on internal sd.
that should it made.
BTW: at first have a lock at my signature!!