Ethereum developers released version 0.7.0 of Solidity, which officially claimed to be a major update to the Solidity language and compiler

Ethereum developers released Solidity 0.7.0 version. Officially, Solidity 0.7.0 is a major update to the Solidity language and compiler. This version removes the external storage mapping function, the keyword “var”, and the constructor no longer needs the default visibility (Visibility), and some syntax changes are also made. The official recommendation is to upgrade all code to make it compatible with Solidity v.0.7.0.