There are several posts here about Iconsoft Phone Extension, all recent versions, have Trial Watermark on the background every few days.
Bellow is a fix from a russiam site, I tried it, and week passed, and no watermarks.
Use any Registry editor (I am using PHM Registry Editor if you don't have one).
Enter the following:
Some more detailed explanation, for people that don't know registry editors:
1. go to HKEY_LOCAL_MACHINE\Comm \Tcpip\Hosts
2. create under Hosts new key, name it: www.iconsoft.com
3. select the new key you just created www.iconsoft.com
4. create in that key a New Binary Value, Name it ExpireTime, and as Value enter: 99 99 99 99 99 99 99
5. create another New Binary Value, Name it ipaddr, and as Value enter: 7F 00 00 01
6. create another key under Hosts: iconsoft.com
7. repeat steps 4 & 5 for the iconsoft.com key