CFM21910 - IFRS 9: transition
IFRS 9 must be applied for periods of account beginning on or after 1 January 2018. The standard must be applied retrospectively, except for some specific exemptions detailed in IFRS 9.
The advice of an advisory accountant should be sought in cases applying the transitional exemptions in IFRS 9.
Further guidance
Change of accounting basis (CFM76000)