I want to create android application for smartwatch with a cellular internet connection that send HTTP post to a server. What android version support should i have? I saw that android 5.1 support cellular network but in Wikipedia it written that only android 7.1.1 support cellular data.
Watches and Phones have thier own OS. Perhaps you found something built to look like a watch that is actually using the phone OS. i wouldnt doubt it as the wear playform is not given the same attention...
But at least in part the actual watch versioning is confusing.
it started out as Android Wear 1.x 2.x then reset to Wear OS 1.x which is now up to version 2.6, all while the latest version for Pie was again renamed to letter version, which is version H... Go figure.
Also if starting now at i wouldnt worry about the older Android Wear hardware, and not even sure if you could buy a new 'Android Wear' watch at this point, so any watch that advertises 'Wear OS by Google' will support Wear OS.
Also I might concider getting a watch with the physical USB connector so you can debugging on the device itself... otherwise you have to manage debugging over bluetooth which at least for me is not always stable on one pc, and have never gotten to work on another...
But such advise is rather particular to me...
Update: it strikes me that you might have been speaking about the target version of Android, which yes admitingly is yet another version to get familiar with developing with wearable android...
Usually it is seen as the target or compile versoin, and from what Im aware the SDK is compatible from version 7.x to the latest 9.0... but perhaps there are eirlier versions that work with the older Android Wear down to what you mention 5.x Im unsure.
Currently i target 8.0 but moving to 8.1 to get at updated libraries im interested in.
And then there are the API Levels to get familiar with... Ya honestly it's really confusing...