Can you coping a group of test from testcomplete v8 to a new project in testcomplete v11?

I'd like to note first that I haven't tried this, and version 8 to 11 is a big jump. However, you could try copying the test files (browse the directories on the computer, not through TestComplete) into a similar location in your new project. Then in TestComplete right click in the Project Explorer and select Add > Existing Item. Then browse to your copied files.

You can upgrade from earliyer version to TC 11 

https://support.smartbear.com/viewarticle/75859/?utm_source=site-search&utm_medium=search-results&utm_campaign=site-search-c&utm_term=how+to+upgrade+to+tc11#_ga=1.176019115.809719160.1405381514

but you can not go back once upgraded.

if you copy and past just some lines ..hope it would not do any harm.

don't think you can copy group of test unless you upgrade.