Compatibility between different Quartus versions

[Altera_Forum]

Hi list,  

I have a project created using Quartus 7.2. Due to internal issues I'm supposed to use Quartus 5.0. But I am not able to open my project files in version 5.0 which gracefully indicates the absence of backward compatibility. Is there any other way out rather than trying to build the entire thingy from scratch? Is there upward compatibility btn these software versions? I mean can I use Quartus 8.1 and open my project files?   Any kind of help would be deeply appreciated. Thanks in advance.:confused:

[Altera_Forum]

The /db directory, which is the database of the last compile, definitely won't work, but when opening it in Q5.0, it should give a message saying it won't be able to open the db and ask if you want to get rid of it, which you can say yes to(or just delete the /db yourself). The next issue is there will be assignments in the .qsf that Q5.0 won't recognize, as they're assignments added since that release. It should error out on those when opening, so just delete them in the .qsf and try again(I would be surprised if it's more than 1 or 2). I believe that should do it. The only other thing I can think of is if the actual .qpf format has changed. You could create a project in Q5.0 and compare. 

(But in essence, the only two project files you need are the .qpf and .qsf, which are readable and editable)

[Altera_Forum]

There are some elements in *.qsf project files or e. g. in Signaltap *.stp files, that are not downward compatible between all versions. When opening a V8.1 project in V7.2, Quartus is showing incompatible *.qsf lines and you can delete them manually. Manual removal of incompatible entries may also help to import a project in V5.0, but I didn't yet try.  

 Also *.stp files have basically readable ASCII format, but very unhandy in part.