Reading the question “HMAC-SHA1 vs HMAC-SHA256”, I figured out that the known attacks on SHA1 don't apply to its HMAC version. So, HMAC-SHA1 is quite strong right now.
In a protocol like SSL, if it gets broken tomorrow, we can “simply” turn off all the cipher-suites that use HMAC-SHA1. But what if it is used as MAC protection for encrypted data storage? Let's say that I decide to use HMAC-SHA1 instead of HMAC-SHA256 and the former gets broken. It would be a problem because the old stored data will continue to have a broken MAC protection.
Would using HMAC-SHA256 help in that case?
To be more precise: Is HMAC-SHA256 likely to be much difficult to break compared to HMAC-SHA1 and are both HMAC-SHA1 and HMAC-SHA256 likely to be broken in the near future?