Which ITIL Version?

If your organization is well into its ITIL journey or if you have ITIL v3 credits, it may be beneficial to take or continue to take ITIL v3 courses so that you can be aligned with others on your team. ITIL 4 has been developed to be fully compatible with the existing certification scheme.
All current ITIL certifications will remain valid and all credits gained can help you continue your ITIL journey in the new certification scheme. However, you should be aware that ITIL v3 exams will retire beginning in July, 2020; a formal timeline has yet to be announced. 
Once ITIL v3 exams have been retired, you will need to take and pass the ITIL 4 Foundation in order to continue with your ITIL education.