Do we need ssl_dh_parameters_length in version 2.3

[MRob via dovecot]

Hi, I couldn't really find documentation about ssl_dh_parameters_length 
except for mention in passing on the page 
https://wiki2.dovecot.org/SSL/DovecotConfiguration

For version 2.3 and above is that setting necessary? If so what are the 
values I can use, is setting it high like 4096 beneficial or make any 
problems for clients?

Thanks for assistance.