Points to keep in mind while upgrading Liferay X.x version to Liferay X.x

Points to keep in mind while upgrading Liferay X.x version to Liferay X.x

Depends mostly on the kind of work you've done on that portal. Even slight upgrades in Liferay, can have major differences in the source code. If this affects the work you've done, it will affect the upgrade too. For example, things will get difficult to update if :

1. You have developed custom portlets, as they will need recompilation for the new runtime
2. Developed Portlets that use ServiceBuilder might need more work than just a recompilation
3. Using Hooks (even simple jsp hooks) might need re-writing. ext hooks will almost certainly need to, and it can become a major pain
4. Changes in OUT OF BOX APIS version to version(There may not be all APIs) ex:- 6.1 to 6.2
1. Calender API has changed
2. Web content API has changed(Journal Article,Structure and templates)
3. UI has lot of changes related to AUI API(if you want use old Api function you can use in declaration 'aui-io-plugin-deprecated')
4. some of the CSS classes might have changed(like tags ex:- search container).
5. you have think about 'how much stable version it is ?'.

On, the other hand, if most of your work had to do with light theming and content management, it could become an relatively easy and painless upgrade.

In any case, make sure to keep a backup of your Liferay Database, because once you upgrade, there is no way to downgrade back to the initial version.

Please look into the steps to migration Liferay 6.1 to 6.2