Hello,
that solidity compiling is a mess 
I’m trying hours to find out why my contracts sometime compile and sometimes not …
Now I got it …
Environment
ganache
remix.ethereum.org
Details
Want to compile that file:
pragma solidity >=0.6.12;
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/access/Ownable.sol";
And get this error:
https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/GSN/Context.sol:1:1: ParserError: Source file requires different compiler version (current compiler is 0.6.12+commit.27d51765.Emscripten.clang) - note that nightly builds are considered to be strictly less than the released version pragma solidity ^0.5.0; ^---------------------^
When I look into the Context.sol (clicking in remix on the error popup):
pragma solidity ^0.5.0;
At github is it the version:
pragma solidity >=0.6.0 <0.8.0;
Shouldn’t my import import the .sol from its own path? What is going on? Is it possible to “refresh” the compiled files in remix after deploying? - I guess thats the point, because I have another contract that use the older version.
Code to reproduce
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/access/Ownable.sol";
Thanks 
When importing via GitHub, you should specify the release tag, otherwise you will get the latest code in the master branch. For OpenZeppelin Contracts you should only use code published in an official release. (see