i have been reading that in order for smartbridges to work, other coins needs to hard fork? is that true?
this is a very important question..
I think Ark can use encoded listeners to achieve smart bridge without the need of a hard fork, I'm not an expert so you are better off asking on the Ark slack
https://arkecosystem.slack.com/No need for hard fork. As said there are 2 approaches:
1) Including "snippet" code in other blockchain for SmartBridge compatibility (would usually require hard fork)
2) Encoded listeners - no need for any fork or consensus on the other blockchain. Encoded listeners act as intermediary (SmartBridge) between blockchains.