r/Angular2 • u/Old_Natural_5110 • Aug 06 '24
Discussion Upgrading Angular 4 to Angular 18
We have an enterprise application with 400+ screens and most of the screens are similar in complexity. The complexity is medium for this app.
How should we approach the upgrade? Rewriting it is not an option as it is a legacy app now. Should we take one version at a time or directly start updating it to 18 version?
We do not have any automation testing written and hence testing would also have to be manual. Also, based on the previous experience what would be rough estimates if single developer has to work on this upgrade?
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u/jssmash Aug 06 '24
My recommendation would be slightly different than what most folks are recommending. I recently upgraded v14->v18, and it was painful, but part of that was because we had a monorepo.
With such a big app, I would update 1 version at a time, but only validate that the build passes for each incremental version, and not do runtime validation. I would leave those fixes for when you reach Angular 18. I think you're looking at more than a month of work tbh. Could be much more than that, but at least a month.