Under the terms of the agreement concluded in August, Sun will license Synchronica's Mobile Gateway SyncML technology to enable over-the-air synchronisation of Sun Java Communications Suite with compatible mobile devices.
Synchronica originally delivered the software components to Sun on schedule in November 2007.
Having accepted the software, Sun has agreed to pay, in three equal instalments in February, July and October 2008, an initial licence fee of $1.8m for the first major version of the software.
Where applicable the US firm will pay further licence fees on a per-user per-annum basis.
Carsten Brinkschulte, chief executive at Synchronica, said: "We are delighted to have received Sun's acceptance of all the licensed components of Mobile Gateway."
Commons Science and Technology Committee calls for new post-Brexit skilled-workers immigration system
Committee calls for visa-free travel and permit-free work for skilled workers
Eleven 'normal' outer moons, and one described as 'oddball' found circling Jupiter
Scientific discovery has found a quadrillion tonnes of diamonds in the earth's mantle
Mobile payment app makes users' details public by default