1. quit Wazapp from within the app (menu -> quit)
2. delete /home/user/.wazapp/*.db file (using Filebox or term)
3. download latest dev .zip from wazapp github ( https://github.com/tgalal/wazapp/zipball/dev )
4. extract .zip on Your pc
5. now zip only /client folder with all subfolders & structure
6. delete wazapp & wazapp_init files from that zip
7. transfer it to Your N9
8. open rooted Filebox (password: rootme) and move that .zip to /opt/waxmppplugin/bin/wazapp folder
9. extract .zip in that folder accepting to overwrite all existing files
10. open terminal, enter devel-su, then rootme as the password
11. execute command: apt-get install python-dateutil (then wait)
12. execute: cd /opt/waxmppplugin/bin/wazapp
13. execute: chmod 755 *
14. exit terminal
15. start Wazapp from Your homescreen
(16. if Wazapp doesn't start -> reboot + step 15)
p.s.: deleting that .db file in step 2 means deleting Your chat history, so bear that in mind
(Thanks to @TMavica and @knobtviker)
After trying all methods to copy the files over, i gave up and used WinSCP to transfer the files, and continued the steps and OMG! this new version kicks A**