web3.eth.subscribe Migration Guide

Breaking Changes

web3.eth.clearSubscriptions

In 1.x, web3.eth.clearSubscriptions returns true on success.

In 4.x, web3.eth.clearSubscriptions returns an Array of subscription ids.

// in 1.x
var subscription = web3.eth.subscribe('newBlockHeaders', function (error, result) {
    if (!error) console.log(result);
});
web3.eth.clearSubscriptions(function (error, success) {
    console.log(success); // true
});

// in 4.x
const subscription = await web3.eth.subscribe('newBlockHeaders');
subscription.unsubscribe().then(
    console.log(), // [...] Array of subsription ids
);