stratum.js

    function handleConfigure(message){
        var extensions = message.params[0];
        var extensionParameters = message.params[1];
        var poolRollingMask = 0x1fffe000;

        // extensions is a list of extension codes defined in BIP310
        // extensionParameters is a dict of parameters for each extension code
        if (extensions.indexOf('version-rolling') != -1) {
            var minerMask = "0x" + extensionParameters['version-rolling.mask'];
            var minBitCount = extensionParameters['version-rolling.min-bit-count'];
            var poolMask = parseInt(poolRollingMask, 16);
            var userMask = parseInt(minerMask, 16);

            sendJson({id: message.id, result: {'version-rolling': true, 'version-rolling.mask': poolMask & userMask}, error: false})
            return;
        }
    }