Is these the last version for iPhone 6

TL;DR: iOS 12.4.3 is probably the last iOS update the iPhone 6 will get.

Based on Apple’s update history, iOS 12.4.3 is likely the last update for iPhone 6. However, Apple did release this update after releasing iOS 13 (which the iPhone 6 isn’t compatible with), and that is unusual. It’s possible that Apple will release further security updates for iOS 12, but it’s unlikely.

That doesn’t mean that the iPhone 6 is useless. My son still uses and enjoys an iPad 2 that can’t go any higher than 9.3.5, released in 2016. If you’re serious about your security and privacy, I would recommend using a newer iPhone, as patching vulnerabilities on iOS 12 is likely no longer an Apple priority.

https://support.apple.com/en-us/HT201222

Currently, 12.4.3; it's probably going to be the final compatible version, but nobody on these boards can say for certain.

iOS 13 requires more RAM than an iPhone 6 has.

(176461)

An update just released for the iPhone 6, 12.4.4.