The SIP API enables Session Initiation Protocol (SIP) applications to be executed in memory limited terminals, and is especially targeted towards mobile phones. The SIP API for J2ME (JSR-180) was introduced in the S60 3rd Edition and is based on the SIP API for J2ME (JSR-180) specification version 1.1.0.
The SIP API for J2ME (JSR-180) is supported in its entirety as specified by the SIP API for J2ME (JSR-180) specification. The push feature (described in section Using PushRegistry) is also supported in its entirety.
Section Class and interface description offers more clarifications on Java package level, describing the adopted implementation/solution of the specification, where it is quite open and leaves room for interpretations.