No, bitcoin isn't the maximum version yet, bitcoin still has a lot of areas that need improvement. Bitcoin is not a perfect coin and as the technology advances improvements are necessary thus, we can expect that bitcoin is not exempted from these improvements.
well for me btc is okay now and not need any improvement . i like the way how it work ( up and down price ) and in my mind , what if btc will improve i think this feature will also be gone which i dont like to happen . they can tweak other coins because there are so many coins on this crypto market . its okay if they can fix or broke those coins because many people wouldnt care at all but bitcoin , nah , its hard to mess with it because btc got alot of base users .
I do not agree with your idea, everything needs improvement and developments with the passing time so is the case with Bitcoin. I am not saying that it is not standing at a stable or secure position, no doubt is it has touched the many steps of development and working as the king in crypt market. But development with time will bring more improvements and it will become more efficient.