If you purchase any license, you are eligible to upgrade to a higher-level license by just paying the difference in the purchase price. Furthermore, you are also eligible to purchase an additional license at the same level at a discounted price.

To see which offers are available to you, you can look them up here:
http://autoblogged.com/purchase/downloads/

WordPress has a reputation of breaking compatibility with third party plugins and themes with each new version release. Although we try to fully test each new WordPress release, sometimes new releases have short beta periods or are even announced with no public beta testing.

To minimize the impact of compatibility issues with WordPress upgrades, we recommend the following:

• Create a test site to try out new releases before deploying them to your production site.
• Create full backups (all files and your database) before performing any upgrades.
• Check our Known Issues page before upgrading.

More Information

• Upgrading WordPress
• Upgrading WordPress Extended
• Common WordPress Installation Problems
• WordPress Release Archive

For the latest information of WordPress compatibility, see http://www.autoblogged.com/support/release-history/

For information on any known issues with the latest WordPress releases, see http://autoblogged.com/support/kb/known-issues/