Converting the charging socket
The Di2 charging socket is very unfavorably located in the bottom bracket area on ST5 models up to summer 2019. Stromer offers the CV9Di2 conversion kit to change this. Find out more at PIMP mySTROMER - ‚Di2 charging socket - ST5 conversion‚
Retrofitting ANT+/BT connectivity
No retrofitting seems necessary for the ST5 models up to summer 2019 (charging port in the bottom bracket area). However, the ST5 with charging port in the right handlebar end do not appear to have ANT+/BT connectivity. However, it can be retrofitted. You can find out how to do this under PIMP mySTROMER - ‚Di2 - Ant+ / Bluetooth retrofit for ST5‚