First of all - TS5 Hype! Since there is neither a section in the forums for TS5 yet nor can I post in the "Off-Topic" area I'm starting this thread here.
During the beta phase there will be obviously some probems/bugs with the client. I'd like to make this a "living" (growning) collection of issues and possible workarounds so every beta tester can expierence TS5 at it's best 
So let's start with those things that are on my mind:
- Muting a client gets resetted after reconnecting
Workaround: Set the clients volume to -200dB instead. But keep in mind that active AGC will cause you to hear that client still a little bit.
FIXED! 
- Added/changed channel icons are not visible
Workaround 1: Restarting the server.
Workaround 2: Clearing the folder "%AppData%\Roaming\TS5Client\cache" while the client is closed - Login to create the free 10 slot server fails
Workaround: Check under account settings if the email you are logged in with is written upper case. If so, login anew with lower case letters.
FIXED! 
- Badges are not displayed
Workaround: Client restart - Compact server tree mode not saved when restarting client
Workaround: Settings>Appearance>Use Compact Tree - See more/all Group Icons
Go to "Developer Tools" by entering this into the adress bar. - BBCode is not working anymore
Use the custom markdown, f.e.: __ __; ** **; ``` ``` - RAM usage goes crazy (like 2~3GB)
Workaround: Client restart seems to be the only option atm - Having the unread message notifier but can't see who wrote
Workaround: You have to check your offline contacts manually atm. - Client crashes when trying to connect on any server (Win10)
Workaround: Installing the big bunch of windows updates you are missing 
Not yet implemented / Work in Progress*:
- managing the permission system
- Server chat (log)
- File transfer
- Moving multiple clients
- Unlimited group chats
- Recording, 3D sound, phonetics
- Setting up client avatars on servers
- Creation of privilege keys
- Setting up channel icons
- Mark clients as buddy in tree (+show custom name)
- Connection status (Ping, paket loss, IP, ...)
- Themes, icon packs, sound packs, plugins
- Mobile App
- being able to delete the free 10 slot server
That's it so far, guess some edits will come soon 
GL & HF with the TS5 beta!
*Some features may not be used any longer in TS5