I am not familiar with the specific software mentioned, but the general rules for finding lost data are as follows.
When you say backup files, you clearly are not referring to the ones that should be stored on media away from your computer? If you do not have a fairly recent copy of all your important data stored on a USB stick or external hard drive, you could potentially have lost all your data as a worst case scenario.
However there is a fair chance that the files still exist in a hidden or system folder, so you need to use the file manager to search with settings that allow you to view all file types on the computer including hidden and system files. These are options which can be selected in the file manager program. Some files are generally hidden from normal view becausevmessing about with them can cause system instabilities or stop the operating system from working. If you find the files you want, make a copy and paste the copy into the directory where the program will expect to find such information. Set the file attributes so that they are not listed as system and/or hidden files. By working using a copy of the files, if you mess something up, you can go back, make another copy and try again. Remember to alter the file manager settings back when you have finished your searches and/or data recovery.
If the files have been deleted, they should still be in the recycle bin and may be recoverable from there.
Very rarely does a program update just delete data from an earlier version. The data is nearly always still there, it is just hidden from view or moved to another directory (which may also be hidden or protected to stop it accidently being deleted.
The correct search parameter is *.ics and not .ics to bring back all files that have .ics as a suffix. .ics will only return files with no prefix or filename but a .ics suffix, something that shouldn't exist, but you can still search for such files.