mobile phone sync with TDE - how the pro is doing it

Hi I have one very important question as well. How are you guys/pros syncing your mobile phones with TDE. Years ago I worked on opensync, which died because of syncml. I am also following the story of syncevolution, but they provided only support for kde4+ I recall the time (must be 10y ago) when I had no issue to sync up my palm III with KDE ... and after this all went wrong. Since the time I have a smart phone it does not work for me. I would never use an external service that is not under my control, but I could run a service on my public server. (Working) solutions are highly appreciated thanks in advance regards