diff --git a/app/models/external_sync.rb b/app/models/external_sync.rb
index bb4fdf1b8..1eff33857 100644
--- a/app/models/external_sync.rb
+++ b/app/models/external_sync.rb
@@ -5,10 +5,6 @@ class ExternalSync < ApplicationModel
 
   class << self
 
-    def sanitized_source_id(source_id)
-      Digest::SHA2.hexdigest(source_id)
-    end
-
     def changed?(object:, previous_changes: {}, current_changes:)
       changed = false
       previous_changes ||= {}
diff --git a/lib/sequencer/sequence/import/exchange/folder_contact.rb b/lib/sequencer/sequence/import/exchange/folder_contact.rb
index c435023f0..05a4ff4d4 100644
--- a/lib/sequencer/sequence/import/exchange/folder_contact.rb
+++ b/lib/sequencer/sequence/import/exchange/folder_contact.rb
@@ -7,6 +7,7 @@ class Sequencer
           def self.sequence
             [
               'Import::Exchange::FolderContact::RemoteId',
+              'Import::Common::RemoteId::CaseSensitive',
               'Import::Exchange::FolderContact::Mapping',
               'Import::Common::Model::Skip::Blank::Mapped',
               'Common::ModelClass::User',
@@ -15,6 +16,7 @@ class Sequencer
               'Import::Common::Model::Associations::Extract',
               'Import::Common::User::Attributes::Downcase',
               'Import::Common::User::Email::CheckValidity',
+              'Import::Ldap::User::Lookup::Attributes',
               'Import::Common::Model::Attributes::AddByIds',
               'Import::Common::Model::Update',
               'Import::Common::Model::Create',
diff --git a/lib/sequencer/unit/import/common/model/external_sync/integrity.rb b/lib/sequencer/unit/import/common/model/external_sync/integrity.rb
index ed7e80be1..ffc7535b7 100644
--- a/lib/sequencer/unit/import/common/model/external_sync/integrity.rb
+++ b/lib/sequencer/unit/import/common/model/external_sync/integrity.rb
@@ -19,8 +19,8 @@ class Sequencer
 
               def up_to_date?
                 return false if entry.blank?
-                return true if entry.source_id == sanitized_remote_id
-                entry.update!(source_id: sanitized_remote_id)
+                return true if entry.source_id == remote_id
+                entry.update!(source_id: remote_id)
                 true
               end
 
@@ -37,15 +37,11 @@ class Sequencer
               def create
                 ::ExternalSync.create(
                   source:    external_sync_source,
-                  source_id: sanitized_remote_id,
+                  source_id: remote_id,
                   object:    model_class.name,
                   o_id:      instance.id
                 )
               end
-
-              def sanitized_remote_id
-                @sanitized_remote_id ||= ::ExternalSync.sanitized_source_id(remote_id)
-              end
             end
           end
         end
diff --git a/lib/sequencer/unit/import/common/model/lookup/external_sync.rb b/lib/sequencer/unit/import/common/model/lookup/external_sync.rb
index 5d8cea80a..90c27c92e 100644
--- a/lib/sequencer/unit/import/common/model/lookup/external_sync.rb
+++ b/lib/sequencer/unit/import/common/model/lookup/external_sync.rb
@@ -14,10 +14,10 @@ class Sequencer
               provides :instance
 
               def process
-                return if !synced_instance
+                return if entry.blank?
 
                 state.provide(:instance) do
-                  model_class.find(synced_instance.o_id)
+                  model_class.find(entry.o_id)
                 end
               rescue => e
                 handle_failure(e)
@@ -25,47 +25,8 @@ class Sequencer
 
               private
 
-              def synced_instance
-                @synced_instance ||= correct_entry || corrected_entry
-              end
-
-              def correct_entry
-                ::ExternalSync.find_by(
-                  source:    external_sync_source,
-                  source_id: sanitized_remote_id,
-                  object:    model_class.name,
-                )
-              end
-
-              def sanitized_remote_id
-                @sanitized_remote_id ||= ::ExternalSync.sanitized_source_id(remote_id)
-              end
-
-              def corrected_entry
-                return if obsolete_entry.blank?
-                obsolete_entry.update!(source_id: sanitized_remote_id)
-                obsolete_entry
-              end
-
-              def obsolete_entry
-                @obsolete_entry ||= begin
-                  if Rails.application.config.db_case_sensitive
-                    case_sensitive_entry
-                  else
-                    case_insensitive_entry
-                  end
-                end
-              end
-
-              def case_sensitive_entry
-                ::ExternalSync.where(
-                  source: external_sync_source,
-                  object: model_class.name,
-                ).where('LOWER(source_id) = LOWER(?)', remote_id).first
-              end
-
-              def case_insensitive_entry
-                ::ExternalSync.find_by(
+              def entry
+                @entry ||= ::ExternalSync.find_by(
                   source:    external_sync_source,
                   source_id: remote_id,
                   object:    model_class.name,
diff --git a/lib/sequencer/unit/import/common/remote_id/case_insensitive.rb b/lib/sequencer/unit/import/common/remote_id/case_insensitive.rb
new file mode 100644
index 000000000..665049844
--- /dev/null
+++ b/lib/sequencer/unit/import/common/remote_id/case_insensitive.rb
@@ -0,0 +1,21 @@
+class Sequencer
+  class Unit
+    module Import
+      module Common
+        module RemoteId
+          class CaseInsensitive < Sequencer::Unit::Base
+
+            uses :remote_id
+            provides :remote_id
+
+            def process
+              state.provide(:remote_id) do
+                remote_id.downcase
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/sequencer/unit/import/common/remote_id/case_sensitive.rb b/lib/sequencer/unit/import/common/remote_id/case_sensitive.rb
new file mode 100644
index 000000000..54a911e1c
--- /dev/null
+++ b/lib/sequencer/unit/import/common/remote_id/case_sensitive.rb
@@ -0,0 +1,21 @@
+class Sequencer
+  class Unit
+    module Import
+      module Common
+        module RemoteId
+          class CaseSensitive < Sequencer::Unit::Base
+
+            uses :remote_id
+            provides :remote_id
+
+            def process
+              state.provide(:remote_id) do
+                Digest::SHA2.hexdigest(state.use(:remote_id))
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/lib/external_sync_spec.rb b/spec/lib/external_sync_spec.rb
index aa9671266..14f4b4cd0 100644
--- a/spec/lib/external_sync_spec.rb
+++ b/spec/lib/external_sync_spec.rb
@@ -2,27 +2,6 @@ require 'rails_helper'
 
 RSpec.describe ExternalSync do
 
-  context '#sanitized_source_id' do
-
-    let(:source_id) { 'AbCdEfG124' }
-
-    it 'sanitizes source ids' do
-      sanitized_source_id = described_class.sanitized_source_id(source_id)
-      expect(sanitized_source_id).to_not eq(source_id)
-    end
-
-    it 'returns case insenstive value' do
-      sanitized_source_id = described_class.sanitized_source_id(source_id)
-      expect(sanitized_source_id).to eq(sanitized_source_id.downcase)
-    end
-
-    it 'avoids case sensitive collitions' do
-      sanitized_source_id           = described_class.sanitized_source_id(source_id)
-      sanitized_source_id_downcased = described_class.sanitized_source_id(source_id.downcase)
-      expect(sanitized_source_id).to_not eq(sanitized_source_id_downcased)
-    end
-  end
-
   context '#changed?' do
 
     it 'keeps ActiveRecord instance unchanged on local but no remote changes' do
diff --git a/spec/lib/sequencer/unit/import/common/model/lookup/external_sync_spec.rb b/spec/lib/sequencer/unit/import/common/model/lookup/external_sync_spec.rb
index e2124e161..e2a2e666e 100644
--- a/spec/lib/sequencer/unit/import/common/model/lookup/external_sync_spec.rb
+++ b/spec/lib/sequencer/unit/import/common/model/lookup/external_sync_spec.rb
@@ -9,7 +9,7 @@ RSpec.describe Sequencer::Unit::Import::Common::Model::Lookup::ExternalSync, seq
 
     ExternalSync.create(
       source:    external_sync_source,
-      source_id: ExternalSync.sanitized_source_id(remote_id),
+      source_id: remote_id,
       o_id:      user.id,
       object:    user.class,
     )
@@ -22,68 +22,4 @@ RSpec.describe Sequencer::Unit::Import::Common::Model::Lookup::ExternalSync, seq
 
     expect(provided[:instance]).to eq(user)
   end
-
-  context 'obsolete plain remote_id' do
-
-    let(:user) { create(:user) }
-    let(:external_sync_source) { 'test' }
-    let(:remote_id) { 'AbCdEfG' }
-
-    it 'finds model_class instance' do
-      ExternalSync.create(
-        source:    external_sync_source,
-        source_id: remote_id,
-        o_id:      user.id,
-        object:    user.class,
-      )
-
-      provided = process(
-        remote_id:            remote_id,
-        model_class:          user.class,
-        external_sync_source: external_sync_source,
-      )
-
-      expect(provided[:instance]).to eq(user)
-    end
-
-    it 'corrects external sync entry' do
-      entry = ExternalSync.create(
-        source:    external_sync_source,
-        source_id: remote_id,
-        o_id:      user.id,
-        object:    user.class,
-      )
-
-      process(
-        remote_id:            remote_id,
-        model_class:          user.class,
-        external_sync_source: external_sync_source,
-      )
-
-      entry.reload
-
-      expect(entry.source_id).to eq(ExternalSync.sanitized_source_id(remote_id))
-    end
-
-    it 'operates case agnostic' do
-      entry = ExternalSync.create(
-        source:    external_sync_source,
-        source_id: remote_id.downcase,
-        o_id:      user.id,
-        object:    user.class,
-      )
-
-      provided = process(
-        remote_id:            remote_id,
-        model_class:          user.class,
-        external_sync_source: external_sync_source,
-      )
-
-      expect(provided[:instance]).to eq(user)
-
-      entry.reload
-
-      expect(entry.source_id).to eq(ExternalSync.sanitized_source_id(remote_id))
-    end
-  end
 end
diff --git a/spec/lib/sequencer/unit/import/common/remote_id/case_insensitive_spec.rb b/spec/lib/sequencer/unit/import/common/remote_id/case_insensitive_spec.rb
new file mode 100644
index 000000000..cc4ffd2ee
--- /dev/null
+++ b/spec/lib/sequencer/unit/import/common/remote_id/case_insensitive_spec.rb
@@ -0,0 +1,15 @@
+require 'rails_helper'
+
+RSpec.describe Sequencer::Unit::Import::Common::RemoteId::CaseInsensitive, sequencer: :unit do
+
+  it 'overwrites the remote_id with the downcased version of it' do
+
+    remote_id = 'SomeRandom@EmailExample.com'
+
+    provided = process(
+      remote_id: remote_id,
+    )
+
+    expect(provided[:remote_id]).to eq(remote_id.downcase)
+  end
+end
diff --git a/spec/lib/sequencer/unit/import/common/remote_id/case_sensitive_spec.rb b/spec/lib/sequencer/unit/import/common/remote_id/case_sensitive_spec.rb
new file mode 100644
index 000000000..fe4096046
--- /dev/null
+++ b/spec/lib/sequencer/unit/import/common/remote_id/case_sensitive_spec.rb
@@ -0,0 +1,16 @@
+require 'rails_helper'
+
+RSpec.describe Sequencer::Unit::Import::Common::RemoteId::CaseSensitive, sequencer: :unit do
+
+  it 'overwrites the remote_id with the the SHA-2 hashed version of it' do
+
+    remote_id = 'Zammad!'
+    hashed    = '07071585f063b37b8288021f541d8c3cee3265f34e258c8b0bd926378ce03c97'
+
+    provided = process(
+      remote_id: remote_id,
+    )
+
+    expect(provided[:remote_id]).to eq(hashed)
+  end
+end