Yes your catalogs can be upgraded to Lightroom CC catalogs.
Usually only one catalog is upgraded automatically to Lightroom CC. You will have to upgrade the rest of your catalogs individually (one of many great arguments for using a single catalog). Use the Lightroom CC command File->Open Catalog.
Your current Lightroom catalog will be updated and you shouldn’t lose your work.
When you install Lightroom from the Creative Cloud it will find the version you currently have and update it. Make sure you backup your catalog and presets before you start the process just to be safe!
May be some old preset would not work either due to the difference in version.( because of incompatibility)
Thank you dj!
Thank you Sarika!
Make sure you backup your catalog and presets before you start the process just to be safe!
Catalogs should be backed up regularly anyway. But there is no need to make backups of your catalog for the purposes of upgrading to Lightroom 6, as the upgrade process leaves untouched the Lightroom 2.5 catalogs.
Glad to help
Yes you are right, but just for being in safe side I asked to create backup.
Thank you, I already have my catalogs backed up