Hacker News Reader

Both of my Rails apps were on 2.3 for this reason for 5+ years, though the new owners might have migrated. When I specced it out for one it would have been 2+ weeks of solid work.

And that was pretty much it. Neither 3 -> 4 nor 4 -> were nearly as painful.

I had a Rails 0.9 app that I'd carefully upgraded to Rails 2.3 (and then done security backports for) running for just over 10 years. Decommissioned it last month. The Rails 3 upgrade was certainly one step too far for that app :)

I realized after 3.x came out that committing to a large framework and associated ecosystem comes with a significant cost/tax that is often not worth it (but sometimes is).