Section 59A(b) in The Companies (Indian Accounting Standards) Rules, 2015
(b)The amendments in paragraphs 30-31 and 33-33D apply to share-based payment transactions that are unvested at the date that an entity first applies the amendments and to share-based payment transactions with a grant date on or after the date that an entity first applies the amendments. For unvested share-based payment transactions granted prior to the date that an entity first applies the amendments, an entity shall remeasure the liability at that date and recognise the effect of the remeasurement in opening retained earnings (or other component of equity, as appropriate) of the reporting period in which the amendments are first applied.
