UPGRADING.md in mongoid-locker-1.0.1 vs UPGRADING.md in mongoid-locker-2.0.0

@@ -1,7 +1,26 @@
-## Upgrading Mongoid Locker
+## Upgrading Mongoid-Locker
 
+## Upgrading to 2.0.0
+
+Mongoid-Locker supports only `5`, `6` and `7` versions of Mongoid.
+Since this version `Mongoid::Locker` uses unique name of locking and time is set by MongoDB. `Mongoid::Locker` no longer uses `locked_until` field and this field may be deleted with `User.all.unset(:locked_until)`. You must define new `locking_name` field of `String` type.
+
+```ruby
+class User
+  include Mongoid::Document
+  include Mongoid::Locker
+
+  field :locking_name, type: String
+  field :locked_at, type: Time
+end
+```
+
+The options `:timeout` and `retry_sleep` of `#with_lock` method was deprecated and have no effect. For details see [RubyDoc.info](https://www.rubydoc.info/gems/mongoid-locker/2.0.0/Mongoid/Locker#with_lock-instance_method).
+If you handle `Mongoid::Locker::LockError` error then this error should be renamed to `Mongoid::Locker::Errors::DocumentCouldNotGetLock`.
+
 ### Upgrading to 1.0.0
+
 `Mongoid::Locker` no longer defines `locked_at` and `locked_until` fields when included. You must define these fields manually.
 
 ```ruby
 class User
   include Mongoid::Document