I don't think so. In the (rare) case that you were using a deprecated function that has now been completely removed, you'll need to adapt the program, but that's no problem. And a few things operate differently. For example if you were multiplying a row vector by a column vector, with automatic expansion (not sure when that was introduced) you can get a matrix instead of a vector, but that's something you'll quickly find out about when you run your test scripts that should produce the same data as the prior version you were using. Still it's best to keep your code current rather than multiple versions of code locked into multiple old versions of MATLAB. For me, it's easier to just work with one version of MATLAB (if possible) and fix anything that might break. But most likely nothing will break for you. Virtually all of my programs work fine in new versions.