SyncML (Synchronization Markup Language) is a protocol standard defined by the Open Mobile Alliance for platform-independent information synchronization.
SyncML is most commonly thought of as a method to synchronize contact and calendar information between some type of handheld device and a computer (personal, or network-based service), such as between a mobile phone and a Horde installation.
Horde includes a SyncML server functionality that allows all SyncML capable clients to replicate their calendar events, tasks, notes, and contacts with Horde. Some phones have a SyncML client included (most modern mobile phones), for others there are SyncML software packages such as:
Horde's SyncML server functionality is implemented in a horde PEAR package named SyncML. This package is designed to be independent from Horde. Other groupware applications can use this package to provide SyncML as well. The only thing that's need to be done is the implementation of a backend interface for their application. Please drop a note on the horde sync mailing list (email@example.com) if you are interested in this.