i'm not able to open my project in Testcomplete 11 after upgaded project suit in TestComplete 12

That is correct. You cannot upgrade a project to a later version and then use it in an older version of Test Complete.

I would suggest restoring your project to it's previous version through your source control or backup process.

Hi Sana,

if you Load your projectsuite in Testcomplete 12 ,Project suite will be updated (insense it can loaded in any TC 12 Version and Above)

but you can't load your project suite below version TC 12 (Example TC 10, 9,8 etc)

Suggestions:

Please Maintain  Same Suite With Different Version Supported

(Low Version Project Suite Can Accepted in High Version of Testcomplete,But High Version Project Suite Can't Accepted in Low Version of TestComplete)

Regards,

Karthick Raj P