I have an Eclipse RCP project that's targeted to Eclipse 3.4. Now that 3.5 is out and I'm using it, and while I don't have any reason to change my plugin to target the 3.5 platform, I'm left wondering how exactly is one supposed to do it.
I can't seem to find any option which lets me change a plugin's target platform after it's been created. The plugin.xml has a line which says <?eclipse version="3.4"?>. It can't be as simple as that right?
The <?eclipse version="3.5"?> entry in the plugin.xml has no affect at run-time. It is purely a hint to the PDE tooling at development time. You do not need to change it to use your bundle in 3.5.
In general, if you are using the public API and not reaching into internals you may not need to make any changes at all to run under 3.5. But take a look at the plug-in migration guide in the help, and the compatibility section of the 3.5 Release Notes.
Also, look at your manifest file. Do you define version ranges for your dependencies? If so, make sure the 3.5 versions of things you require are still within the upper bounds of those ranges.