diff --git a/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Main/Init.pm b/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Main/Init.pm
index 0272e75b5..ddb52931d 100644
--- a/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Main/Init.pm
+++ b/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Main/Init.pm
@@ -356,11 +356,7 @@ sub reloadConf {
 
     # Clean $req->pdata after authentication
     push @{ $self->endAuth }, sub {
-
-        my $tmp =
-          ( ref( $_[0]->pdata->{keepPdata} ) eq 'ARRAY' )
-          ? $_[0]->pdata->{keepPdata}
-          : [];
+        my $tmp = $_[0]->pdata->{keepPdata} //= [];
         foreach my $k ( keys %{ $_[0]->pdata } ) {
             unless ( grep { $_ eq $k } @$tmp ) {
                 $self->logger->debug("Removing $k from pdata");
diff --git a/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Main/Process.pm b/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Main/Process.pm
index f73887179..c30a28f97 100644
--- a/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Main/Process.pm
+++ b/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Main/Process.pm
@@ -162,10 +162,7 @@ sub authLogout {
     my ( $self, $req ) = @_;
     my $res = $self->_authentication->authLogout($req);
     $self->logger->debug('Cleaning pdata');
-    my $tmp =
-      ( ref( $req->pdata->{keepPdata} ) eq 'ARRAY' )
-      ? $req->pdata->{keepPdata}
-      : [];
+    my $tmp = $req->pdata->{keepPdata} //= [];
     foreach my $k ( keys %{ $req->pdata } ) {
         delete $req->pdata->{$k} unless ( grep { $_ eq $k } @$tmp );
     }
diff --git a/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Main/Run.pm b/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Main/Run.pm
index 7c42a31be..3f479d13a 100644
--- a/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Main/Run.pm
+++ b/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Main/Run.pm
@@ -63,6 +63,13 @@ sub handler {
             $self->logger->error("Bad JSON content in cookie pdata");
             $req->pdata( {} );
         }
+
+        # Avoid fatal errors when using old keepPdata format
+        if ( $req->pdata->{keepPdata}
+            and not( ref $req->pdata->{keepPdata} eq "ARRAY" ) )
+        {
+            $req->pdata->{keepPdata} = [];
+        }
     }
     my $res = $self->Lemonldap::NG::Common::PSGI::Router::handler($req);