I could see a lot of depreciations done in Rails 1.2 which will be removed from rails version 2. But since I could not get all the depreciations at one single location, I thought of summarizing them.

I would like all the users to comment on this listing to make it better and hence more use-able

1. Use of @ before system variables like session, flash, request etc.
Use cookies, request, response, headers, params, session, flash instead of their counter-parts with @ in the beginning

2. Use smtp_settings for Action mailer in environment.rb file instead of server.settings

3. Start using <% form_tag :action => "create" do%> ... <% end %> instead of traditional <%= start_form_tag %> and <%= end_form_tag %>, see DHH's note on this Here