anyone can elaborate, how backward compatibility is defined in relation to smart contracts?

thanks. I think so in the contracts not define the token value in Ether. I don't now.
Now I try the execute the project in Ganache with Truffle and OpenZeppelin and get problemas with migrations. How migrate in Truffle this contracts ?

import 'openzeppelin-solidity/contracts/token/ERC721/ERC721Full.sol';
import 'openzeppelin-solidity/contracts/math/SafeMath.sol';

I try this:

const ViperToken = artifacts.require("ViperToken");
const SafeMath= artifacts.require("SafeMath");
const ERC721Full = artifacts.require("ERC721Full");



module.exports = function(deployer) {
deployer.deploy(ViperToken);
deployer.deploy(ERC721Full);
deployer.deploy(SafeMath);
};


and get:


Deploying 'ERC721Full'
----------------------
Error: * Deployment Failed *

"ERC721Full" -- Invalid number of parameters for "undefined". Got 0 expected 2!.

you are trying to deploy the viper token right? you don't need to deploy erc721 & safemath separately. as you are inheriting them, the compilation should have their byte code. try deploying just the viper token contract

ok, but i get the same result.
Not work when I try transfer viper token between accounts

there could be a couple of things:
1. the accounts in metamask mayn't be set up the same like in ganche (cause you in 123.0.0.1:7445) network. The account 1 in metamask != accounts[0] in ganche
2. you have not added the token address in your metamask wallet to show
3. you can try deploying it to ropsten and check for those tokens in etherscan, this is what i would do

thanks, and you know where I can charge ether for the ropsten private testnet?

https://faucet.ropsten.be/