Solhint

Avoid to use .call.value()().

Avoid to use low level calls.

Compiler version must satisfy a semver requirement.

Explicitly mark visibility in function.

Explicitly mark all external contracts as trusted or untrusted.

Avoid multiple calls of send method in single transaction.

Fallback function must be simple.

Do not rely on block.blockhash. Miners can influence its value.

Use keccak256 instead of deprecated sha3.

Use selfdestruct instead of deprecated suicide.

throw is deprecated, avoid to use it.

Avoid to use tx.origin.

Check result of send call.

Avoid to use inline assembly. It is acceptable only in rare cases.

Avoid making time-based decisions in your business logic.

Possible reentrancy vulnerabilities. Avoid state changes after transfer.

Explicitly mark visibility of state.