Rewrites lead to all those wonderful feature-removing and compatibility-breaking scenarios that you see in “new versions” of software. They can really suck for

Rewrites lead to all those wonderful feature-removing and compatibility-breaking scenarios that you see in “new versions” of software. They can really suck for consumers and that is reason alone to be much more cautious. On the other hand, you can’t expect to keep your entire software world standing still. At some point, the operating system or even the hardware will make it really hard to keep an old code base going, and you’ll have to do very creative things just to keep it all working. And no, you typically don’t have the freedom to force people to use some ancient system for your benefit; you’re not in a vacuum, your users are doing lots of other things and their other apps are going to keep moving even if you don’t. You will reach a point of real regret if you don’t spend at least some time to move code to more modern concepts/languages/libraries. It doesn’t have to be 100% at once, nor does it have to be an outright replacement; leverage multi-language bindings, testing frameworks, etc. and beta users to make progress. And whatever you do, never release a “MyApp 5” that is a completely different code base than “MyApp 4”; this just aggravates people when nothing works quite right. You need MyApp 4.1, 4.2, 4.3, 4.4, etc.