First what it says in the Official Journal:
ETSI EN 301 511 V9.0.2
Global System for Mobile communications (GSM); Harmonized EN for mobile stations in the GSM 900 and GSM 1800 bands covering essential requirements under article 3.2 of the R&TTE directive (1999/5/EC)
Notice: This harmonised standard provides presumption of conformity with the essential requirements of Directive 2014/53/EU if also the receiving parameters in clause(s) 4.2.20, 4.2.21 and 4.2.26 are applied
ETSI EN 301 511 V12.5.1
Global System for Mobile communications (GSM); Mobile Stations (MS) equipment; Harmonised Standard covering the essential requirements of article 3.2 of Directive 2014/53/EU
The new (or amended) standard has the same scope as the superseded standard. On the date stated, the superseded standard ceases to give presumption of conformity with the essential or other requirements of the relevant Union legislation.
The new standard should be adhered to at the latest by the 30th of April 2019.
Our lab have advised that it would take longer to determine what supplementary testing would be required compared to simply re-testing. That said if as an existing customer have re-testing to the new carried out by CTI they are prepared to offer a 10% discount.