DPF end of life calculation is just that. It is coded function in the Kombi which is set to approx. 250,000 km. A replacement reminder message is display, but no risk of no start or reduced performance.
If you are not getting DPF specific faults - then this can be reset (marking DPF as replaced) using ISTA or a Tool32 job.
Make sure your engine thermostat has been replaced and the engine is running up to full temp. There are many other threads on this.