После обновления до Rails 4.1.4 с Rails 3.2 доступ к приложению с помощью существующего сеанса (из более старой версии Rails 3.2) вызывает внутреннюю ошибку сервера. трассировка:

JSON::ParserError - 795: unexpected token at {
I"session_id:ETI"%fa78a4ee07ac952c9b034ebc6199f30b;':
  /Users/.../.rvm/rubies/ruby-2.1.0/lib/ruby/2.1.0/json/common.rb:155:in `parse'
  actionpack (4.1.4) lib/action_dispatch/middleware/cookies.rb:388:in `load'
  actionpack (4.1.4) lib/action_dispatch/middleware/cookies.rb:428:in `deserialize'
  actionpack (4.1.4) lib/action_dispatch/middleware/cookies.rb:183:in `verify_and_upgrade_legacy_signed_message'
  actionpack (4.1.4) lib/action_dispatch/middleware/cookies.rb:550:in `[]'
  actionpack (4.1.4) lib/action_dispatch/middleware/session/cookie_store.rb:114:in `get_cookie'
  actionpack (4.1.4) lib/action_dispatch/middleware/session/cookie_store.rb:90:in `block in unpacked_cookie_data'
  actionpack (4.1.4) lib/action_dispatch/middleware/session/abstract_store.rb:51:in `stale_session_check!'
  actionpack (4.1.4) lib/action_dispatch/middleware/session/cookie_store.rb:89:in `unpacked_cookie_data'
  actionpack (4.1.4) lib/action_dispatch/middleware/session/cookie_store.rb:83:in `block in extract_session_id'
  actionpack (4.1.4) lib/action_dispatch/middleware/session/abstract_store.rb:51:in `stale_session_check!'
  actionpack (4.1.4) lib/action_dispatch/middleware/session/cookie_store.rb:82:in `extract_session_id'
  actionpack (4.1.4) lib/action_dispatch/request/session.rb:49:in `block in []'
  actionpack (4.1.4) lib/action_dispatch/request/session.rb:48:in `[]'
  actionpack (4.1.4) lib/action_dispatch/request/session.rb:70:in `id'
  rack (1.5.2) lib/rack/session/abstract/id.rb:282:in `current_session_id'
  rack (1.5.2) lib/rack/session/abstract/id.rb:288:in `session_exists?'
  actionpack (4.1.4) lib/action_dispatch/request/session.rb:152:in `exists?'
  actionpack (4.1.4) lib/action_dispatch/request/session.rb:172:in `load_for_read!'
  actionpack (4.1.4) lib/action_dispatch/request/session.rb:89:in `[]'
  warden (1.2.3) lib/warden/session_serializer.rb:30:in `fetch'
  warden (1.2.3) lib/warden/proxy.rb:212:in `user'
  warden (1.2.3) lib/warden/proxy.rb:318:in `_perform_authentication'
  warden (1.2.3) lib/warden/proxy.rb:104:in `authenticate'
  warden (1.2.3) lib/warden/proxy.rb:114:in `authenticate?'
  devise (3.2.4) lib/devise/rails/routes.rb:460:in `block in constraints_for'
  actionpack (4.1.4) lib/action_dispatch/routing/mapper.rb:38:in `block in matches?'
  actionpack (4.1.4) lib/action_dispatch/routing/mapper.rb:36:in `matches?'
  actionpack (4.1.4) lib/action_dispatch/routing/mapper.rb:45:in `call'
  actionpack (4.1.4) lib/action_dispatch/journey/router.rb:71:in `block in call'
  actionpack (4.1.4) lib/action_dispatch/journey/router.rb:59:in `call'
  actionpack (4.1.4) lib/action_dispatch/routing/route_set.rb:678:in `call'
  ...

Я пытался изменить имя ключа cookie сеанса, но, похоже, он застрял наsession_id.

# initializers/session_store.rb
MyApp::Application.config.session_store :cookie_store, key: 'myapp_session'

Пожалуйста помоги! Отличным решением также было бы удалить все сессионные куки до того, как они попадут в промежуточное ПО рельсов, но я понятия не имею, как это сделать ..