Easy question for server creators

[__MM__]

I'm just new to the *creating a private server* world. and i have internet problems that stops me from download the client they're asking for before starting their guides.
Will it be okay if i went thro with their guide while using a random client like v1.255? and why not of this way wont work.
thanks so much <3

[JuliaRocks]

Server side's client version should match with the client version ._. .