Make a copy of your qkey if you want to keep your statistics.
(For windows you will usually find the qkey in folder: C:\Program Files (x86)\UrbanTerror\ .
For Linux it is in the hidden .q3a folder)
Choose a new folder name for the 4.3.4 software when you install it, for example:
C:\Program Files (x86)\UrbanTerror434
(but it could be stored anywhere)
Replace the qkey in your new folder by the saved one.
We hope to see you soon.
edit: Topic name and post updated to reflect the 4.3.4 update //Mazfer