Imaginesim have released a Prepar3Dv2 version of their current WSSS Singapore Changi as part of their legacy range. This will be a stop-gap solution for your flight plans because a completely new-build WSSS Singapore will be released later this year.
If you have already purchased the FSX version of WSSS then you get the Prepar3D version for free. There is also a comprehensive update for users of the FSX version bringing increased performance and visual improvements. Further information at The Imaginesim Homepage.