What problems have you encountered when not deprecating or deprecating features after updates? Especially for web applications and databases?
What guides are there for deprecation? I found Java: http://download.oracle.com/javase/1.5.0/docs/guide/javadoc/deprecation/deprecation.html
The problems I can think:
+ a 404 when old links point to old locations.
+ Form pages submit old form data instead of new form data.
+ Submitted data tries to go to a database table that doesn't exist.
What's the best way to determine a minimum time for the deprecation? What about public APIs?