The VHF Band 8.33 KHz Channel Spacing requirement first came into force in 1999 for the 30 European States in Eurocontrol, applicable to all aircraft operating above FL245. Just about every Public Transport Aircraft that operated routes within or across Europe was brought into compliance back then.
EASA brought the level down to FL 195 in 2007. The rule was further extended to ground level on 16 Nov.2012. All aircraft operating in European airspace must be equipped with VHF 8.33 KHz channel spacing from 01 January 2018. The rule applies to all State aircraft (i.e. Military), with exception granted only to those that will be withdrawn from service by 31 December 2025.
The rule doesn't apply to the UHF Band which is not used by civilian operators