ec
as defined in Directive (EU) 2016/797 of the European Parliament and of the Council of 11 May…, Article 2, point (14) (Definitions)
(14)
‘upgrading’ means any major modification work on a subsystem or part of it which results in a change in the technical file accompanying the ‘EC’ declaration of verification, if that technical file exists, and which improves the overall performance of the subsystem;