I just upgraded the dc++ core of LinuxDC++ from 0.674 to 0.691. There are a lot of nice features and bug fixes in this. This is from the changelog (pay special note to the warning):

* Upgraded the client core to version 0.691:
* All sources to downloads will be lost (not the files) due to Queue.xml core changes.
* Some settings will have to be reconfigured (namely connection mode & speed).
* Added features:
* Disconnect slow users.
* IP field can accept a hostname.
* Markers for ZDownloads, TTH Trees, TTH Check, Secure (Not supported) & Rollback.
* Show timestamps options.
* Log Hub, PM and Filelist transfers.
* Option to use Monospaced font for Hub & PM (thanks UrkeMMI).
* Tab bolding options for Hub, PM, Search, Finished Downloads and Finished Uploads.
* Notification when searching too soon.
* Fixed bugs:
* Bug #6103: crashes when have no permission to create file/directory (untested)
* Bug #6294: Hub topics not working
* Bug #6462: User list loading very slow (on Open DC hubs)
* Switching connection mode requires a restart.
* Completely rewrote settings dialog to make room for the new options.
* Hid most of the unimplemented settings.
* Fixed bug #7651: GUI Freeze (in downloadqueue)
* Rewrote the character encoding code to use a user-specified fallback locale (default CP1252)
if current locale fails. Not a 100% fix for unicode issues, but a start.