diff --git a/Kernel/System/MigrateFromOTRS/CloneDB/Driver/Base.pm b/Kernel/System/MigrateFromOTRS/CloneDB/Driver/Base.pm
index 6ef2a25902..f78e442601 100644
--- a/Kernel/System/MigrateFromOTRS/CloneDB/Driver/Base.pm
+++ b/Kernel/System/MigrateFromOTRS/CloneDB/Driver/Base.pm
@@ -342,8 +342,9 @@ sub DataTransfer {
     # Open for writing as the file usually does not exist yet.
     # This approach assumes that the the webserver processes are running on a single machine.
     my $LockFile = join '/', $ConfigObject->Get('Home'), 'var/tmp/migrate_from_otrs.lock';
-    # TODO: why still warnings from Perl::Critic ??
+
     ## no critic qw(OTOBO::ProhibitLowPrecedenceOps OTOBO::ProhibitOpen InputOutput::RequireBriefOpen)
+
     open my $LockFh, '>', $LockFile or do {
         $MigrationBaseObject->MigrationLog(
             String   => "Could not open lockfile $LockFile; $!",
diff --git a/Kernel/System/MigrateFromOTRS/OTOBOCopyFilesFromOTRS.pm b/Kernel/System/MigrateFromOTRS/OTOBOCopyFilesFromOTRS.pm
index 1eadd4639b..b096b18c61 100644
--- a/Kernel/System/MigrateFromOTRS/OTOBOCopyFilesFromOTRS.pm
+++ b/Kernel/System/MigrateFromOTRS/OTOBOCopyFilesFromOTRS.pm
@@ -345,7 +345,6 @@ sub ReConfigure {
 
     # Write new config file, the file handle is autoclosed as it is lexical to the block
     {
-        # TODO: find out why the warning is still reported
         open my $Out, '>:encoding(utf-8)', $ConfigFile
             or return "Can't open $ConfigFile: $!"; ## no critic qw(OTOBO::ProhibitLowPrecedenceOps)
         print $Out $Config;
diff --git a/Kernel/System/MigrateFromOTRS/OTOBOOTRSConnectionCheck.pm b/Kernel/System/MigrateFromOTRS/OTOBOOTRSConnectionCheck.pm
index 9b427e7af3..78f4d44f10 100644
--- a/Kernel/System/MigrateFromOTRS/OTOBOOTRSConnectionCheck.pm
+++ b/Kernel/System/MigrateFromOTRS/OTOBOOTRSConnectionCheck.pm
@@ -244,7 +244,6 @@ sub _CheckConfigpmAndWriteCache {
     my %CacheOptions;
 
     {
-        ## TODO: why does Perl::Critic still complain about OTOBO::ProhibitOpen ??
         open( my $In, '<', $ConfigFile )            ## no critic qw(OTOBO::ProhibitOpen)
             or return "Can't open $ConfigFile: $!"; ## no critic qw(OTOBO::ProhibitLowPrecedenceOps)
 
diff --git a/Kernel/System/UnitTest/RegisterDriver.pm b/Kernel/System/UnitTest/RegisterDriver.pm
index 0e9d09d8a7..57962e6b79 100644
--- a/Kernel/System/UnitTest/RegisterDriver.pm
+++ b/Kernel/System/UnitTest/RegisterDriver.pm
@@ -41,9 +41,8 @@ use utf8;
 # OTOBO modules
 use Kernel::System::ObjectManager;
 
-# TODO: why still warnings from Perl::Critic ??, find better location for the no critic
-## no critic qw(OTOBO::RequireCamelCase)
-sub import {
+
+sub import { ## no critic qw(OTOBO::RequireCamelCase)
 
     # RegisterDriver is meant for test scripts,
     # meaning that each sript has it's own process.
diff --git a/Kernel/System/UnitTest/Selenium.pm b/Kernel/System/UnitTest/Selenium.pm
index 5f3cd1edd3..1c9371f92b 100644
--- a/Kernel/System/UnitTest/Selenium.pm
+++ b/Kernel/System/UnitTest/Selenium.pm
@@ -259,8 +259,8 @@ Therefore override that subroutine.
 
 =cut
 
-# TODO: where to put 'no critic qw(OTOBO::RequireCamelCase)'
-sub button_up {
+sub button_up { ## no critic qw(OTOBO::RequireCamelCase)
+
     my ($Self) = @_;
 
     if ( $Self->{is_wd3}
diff --git a/Kernel/System/Web/Exception.pm b/Kernel/System/Web/Exception.pm
index c694a33bba..4e7a874b19 100644
--- a/Kernel/System/Web/Exception.pm
+++ b/Kernel/System/Web/Exception.pm
@@ -78,9 +78,7 @@ make use of a caught exception object
 
 =cut
 
-# TODO: why still warnings from Perl::Critic ??
-## no critic qw(OTOBO::RequireCamelCase)
-sub as_psgi {
+sub as_psgi { ## no critic qw(OTOBO::RequireCamelCase)
     my $Self = shift;
 
     # The thrower created the error message
diff --git a/scripts/backup.pl b/scripts/backup.pl
index b079123e9e..a42447ccea 100755
--- a/scripts/backup.pl
+++ b/scripts/backup.pl
@@ -194,7 +194,6 @@
 my $Directory = join '/',
     $BackupDir,
     $SystemDTObject->Format( Format => '%Y-%m-%d_%H-%M-%S' );
-# TODO: why still warnings from Perl::Critic ??
 mkdir $Directory or die "ERROR: Can't create directory: $Directory: $!"; ## no critic qw(OTOBO::ProhibitLowPrecedenceOps)
 
 # backup application
@@ -489,7 +488,6 @@ sub BackupForMigrateFromOTRS {
 
         # now adapt the relevant lines
         # TODO: make this less nasty. Make it nicety.
-        # TODO: why still warnings from Perl::Critic ?? Maybe the line count is messed up.
         open my $Adapted, '>', $AdaptedSchemaDumpFile                   ## no critic qw(OTOBO::ProhibitOpen)
             or die "Can't open $AdaptedSchemaDumpFile for writing: $!"; ## no critic qw(OTOBO::ProhibitLowPrecedenceOps)
         say $Adapted "-- adapted by $0";