When will these changes take effect?

The end of the year 2021 is seen as the key deadline for the transition.
In March 2021, the Financial Conduct Authority (FCA), which oversees the LIBOR process, and the Inter-Continental Exchange Benchmarking Administration (IBA), the administrator of LIBOR, have confirmed the cessation dates of LIBOR rates. It is important to note that:

• Publication of LIBOR rates, for most currencies and tenors/maturities, will cease to exist on 31st December 2021
  
• Publication of selected USD LIBOR rates will be available until end of June 2023, while these will be available for transitioning existing USD LIBOR contracts with more complex settings
• No new contracts based on LIBOR rates will be issued as from 31st December 2021 (independent of the currency and maturity) in a vast majority on markets