Co-worker letter - Supervisor Joined company after Me

Please clarify the below scenario.

I have worked in a company from Feb 2011 to May 2018. My last supervisor joined the company in May 2014 only and I was working under him till May 2018.

Now if he gives me letter for the period Feb 2011 to May 2018, will it be acceptable as he himself joined the company in May 2014?

If the supervisor joined the company after you, then he can write letter only for the tenure that he worked with you.

You would need another letter from another co-worker for your remaining work time.