I own Lightroom version 2. Can this version be upgraded or must I purchase the full software of a more up to date version?
You can purchase the upgrade to Lightroom 5 from Adobe, go to Products
As mentioned, you can upgrade to LR 5 from any earlier version.
Just make sure that your computer hardware and operating system can run it first
System requirements | Lightroom
e.g. Lightroom 5 will not run on Windows XP or Vista or Mac OS X earlier than 10.7.
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