FreeTimeSync is the first S60 3rd's time synchronization application, it is based on the NTP (Network Time Protocol), which provides high-precision time correction (on LAN less than 1 ms, on Internet dozens of milliseconds), and only causes little network flow.
FreeTimeSync needs to sign before installion. You can sign it with your dev cert. If you don't know about cert and sign, please visit www.symbiansigned.com and follow the instructions to get FreeTimeSync Open signed.