s60v3 uses a hardened version of Symbian OS (v9.1), which has mandatory code signing. In S60v3, a user may install only programs that have a certificate from a registered developer, unless the user disables that feature or modify the phone's firmware through third-party hacks that circumvent the mandatory signing restrictions. This makes software written for S60 1st Edition or 2nd Edition not binary-compatible with S60v3.

In 2006, a "Designed for S60 Devices" logo program for developers was launched. The logotype can be used with conforming programs (Symbian or Java).