Currently, the multisig descriptor constructions are limited to 16 keys only possibly because of template parsing reasons. Under p2sh context, such scripts would be invalid anyway because of 520-byte rule, but we can support up to 20 keys for CHECKMULTISIG in witness script context. 


const CScriptNum nLockTime(stacktop(-1), fRequireMinimal, 5);
                    
                    
                    
                    if (nLockTime < 0)
                        return set_error(serror, SCRIPT_ERR_NEGATIVE_LOCKTIME);
                    
                    if (!checker.CheckLockTime(nLockTime))
                        return set_error(serror, SCRIPT_ERR_UNSATISFIED_LOCKTIME);
                    break;
                }
                case OP_CHECKSEQUENCEVERIFY:
                {
                    if (!(flags & SCRIPT_VERIFY_CHECKSEQUENCEVERIFY)) {
                        
                        break;
                    }
                    if (stack.size() < 1)
                        return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
                    
                    
                    
                    const CScriptNum nSequence(stacktop(-1), fRequireMinimal, 5);