Got an email from JT about this update yesterday......
' As you have bought the Just Trains S7+1 Advanced Underground Stock add-on, either on its own or in the Bundle with Metropolitan Line, we're letting you know that new v.102 software is now available, providing the following updates:
Non-operating auto-numbering for carriages now operational De-icing trains now identified by white dot on cab exterior De-icing carriage units now identified by blue dot on the side of the de-ice car Non-operating de-ice function on TCMS screen now operational
Official recommendation from us here is to apply the update, although none of our scenarios using the S7+1 DR version will be affected if you don't bother. That of course can change in the future so it's prudent to keep up to date. There may also be other less well known issues being fixed in the background too.