[jfaucett]

> until you need to upgrade, then you have months of no business value delivery and need to bring...

This is not the case in my experience. I've upgraded pretty decent sized apps (hundreds of models,lines of routes, etc) and in my experience it would take a couple hours a day spread out over a few days a month and then I was done (for versions: 3-4 and 4-5, never done 3-5).

I would say most of the problem is making sure everyone on the team just keeps all functionality as-is. It can be tempting for team members to refactor as they go through but this then becomes a huge time-sync. Anyways, thats my exp on rails but I have no other frameworks to compare it to.

Has anyone migrated a massive app from some PHP Framework like Symfony or from a java framework like Play, or any framework with a large code base?

I have had to upgrade massive systems that were not done with any framework and full of one-off solutions with in-house developed libraries and it was an absolute nightmare, but I'm sure this depends on the language and team. However, in general I think an open-source library used by millions or even hundreds of people is going to have better documentation, bug coverage, support, etc. than something done in house, just IMHO.

So I guess my question would be, what does the alternative look like?

[thibaut_barrere]

My experience looks like yours - in-house frameworks (e.g. typically in banks) are a mess when it comes to upgrading.

[cevn]

I agree with your post but just wanted to throw out that it's time sink instead of time sync ;) imagine all that time going down the drain!