Multisite with different versions (4.2 and 4.3)

[Patricia43]

I have a number of Drupal sites in the same host ... one of them uses CiviCRM 4.2.
Is it possible for me to use CiviCRM 4.3 for a different site or would this break the first site?

[Eileen]

I'm not quite clear what the question is.

One CiviCRM database can only be association with one CiviCRM version. When you upgrade the CiviCRM tables are substantially changed

However, if you have multiple sites/databases sharing the same codebase you can put a different version of CiviCRM into the modules directory for one site in order to upgrade that site/database to a later version.

[Patricia43]

Eileen ... Thank you, your answer was exactly what I was looking for. However, when I proceeded I realized that the 4.2 version was in a separate sub-directory and therefore would not interfere with the new 4.3 version.