I don't know what distro you use, but you should be able to run kopete from
the 4.x series under any environment. I know most distro's had problems with
integrating kde4 apps into the standard launchers (such as the 3.5 kmenu),
but it should have worked from the command line.
Posted Nov 26, 2009 7:40 UTC (Thu) by JoeF (subscriber, #4486)
[Link]
Slackware 12.2, which doesn't have KDE4. Slackware 13 has KDE4, and it didn't have KDE3 anymore, which is why I didn't upgrade. Eventually, Patrick re-added KDE3 to Slack-current/extra, I guess due to popular demand...
Repositioning the KDE Brand (KDE.News)
Posted Nov 26, 2009 19:42 UTC (Thu) by aseigo (guest, #18394)
[Link]
So your point was that your distribution didn't provide KDE4 packages on the version with KDE3 so you couldn't mix and match. Well, that's a distribution issue, nothing inherent in what KDE upstream does.
KDE4 apps run just fine in a KDE3 workspace and elsewhere, and vice versa.