Devise signin stopped working after upgrading devise(2.2.2 -> 3.2.4) and rails(3.2.13 -> 4.1.0) -

Devise signin stopped working after upgrading devise(2.2.2 -> 3.2.4) and rails(3.2.13 -> 4.1.0) -

i migrated rails app from

rails3.2.13/devise2.2.2 ---> rails4.1.0/devise3.2.4

i made alter in devise.rb

config.pepper --> config.secret_key

but not able login in app using existing password. have reset password , after works fine. think should related encryption done password.

what other alter need , users of app can utilize existing password ?

ruby-on-rails ruby-on-rails-4 devise ruby-on-rails-3.2