Interestingly I asked Mitsubishi technical about this recently as mine are getting to the end of their life :
"I can confirm that the Mitsubishi Outlander PHEV is fitted with 225/55R18 98H Toyo tyres, as standard. Whilst we would recommend that replacements should be a like for like replacement, it is the case that you can use any tyre, so long as it meets this size specification.
As the vehicle is fitted with a Tyre Pressure Monitoring System (TPMS), it is important that all four tyres are the same size make, model and tyre tread. Any differences will be detected by the TPMS and may cause issue with the vehicle operation."
So as I read that , if I change a tyre and it's not like for like I need to change all four?