Splunk Version upgrade 9.0.3 to 9.1.0

[Sathish28]

Hi All,

I am planning to upgrade Splunk Enterprise app in production 

Our Splunk Environment has
1 - Cluster master
4 - indexer
1 - deployment server
1- Search Head
1- monitoring console
1- License Master

is it possible to have the Search head in 9.0.3 version and the remaining Splunk server to be upgrade to 9.1.0 
the search head role is provided to other servers also in our environment

[PaulPanther]

Check out:

[..]

• The search head must be at the same or a higher level than the search peers. See the note later in this section for a precise definition of "level" in this context.

[..]

System requirements and other deployment considerations for distributed search - Splunk Documentatio...