Compatibility of project files created with old Quartus versions

Hello,

I have to deal with several designs for the EPM7128STC100-7F PLD using Quartus II. They were created using old versions such as Quartus II 9.1 or 4.0 Web Edition. Is it safe to work with the current version of Quartus (the latest one that works with MAX7000 PLDs is 13.0sp1, as I understand it) or is it recommended to use the same version as was used to create the files?

Regards,

Adrian