There are two scenarios where using SimpleTreat 3.1 is no longer adequate:
1) You must use SimpleTreat 4.0 for active substance CARs submitted to ECHA (and consecutive product authorisation after approval of the active substance) after July 2017 (more precisely after 25 July 2017, i.e. six months after the decision at WG-I-2017).
2) For product authorisation you must use SimpleTreat 4.0 for applications submitted after January 2019 (more precisely after 25 January 2019, i.e. two years after the WG decision) (see also the TAB v2.0, ENV 9 - link on the webpage https://echa.europa.eu/en/guidance-documents/guidance-on-biocides-legislation/emission-scenario-documents).