my %hash = $VAR1 = {
          '900000001' => {
                           'Network1' => [
                                              'Not used',
                                              'Not used',
                                              'Not used',
                                              'Not used'
                                            ],
                           'Network1 ENV' => [
                                                   '2020-09-09T18:36:50.000Z',
                                                   '2020-09-09T18:36:50.000Z'
                                                 ],
                           'NETOWORK2' => [
                                              '2021-03-10T18:15:54.000Z',
                                              '2020-12-17T19:36:21.000Z',
                                              '2021-03-10T18:15:54.000Z'
                                            ]
                         },
          '266000003' => {
                           'Network1 ENV' => [
                                                   '2021-03-08T13:34:59.000Z'
                                                 ]
                         },
          '566000003' => {
                           'Network1 ENV' => [
                                                   '2020-09-09T18:36:50.000Z',
                                                   '2020-09-09T18:36:50.000Z',
                                                   '2020-09-09T18:36:50.000Z'
                                                 ],
                           'NETOWORK2' => [
                                              '2020-12-17T19:36:21.000Z',
                                              '2020-12-17T19:36:21.000Z',
                                              '2020-12-17T19:36:21.000Z',
                                              '2020-12-17T19:36:21.000Z',
                                              '2020-12-17T19:36:21.000Z',
                                              '2020-12-17T19:36:21.000Z',
                                              '2020-12-17T19:36:21.000Z',
                                              '2020-12-17T19:36:21.000Z',
                                              '2021-03-10T18:15:54.000Z',
                                              '2021-03-10T18:15:54.000Z',
                                              '2020-12-17T19:36:21.000Z',
                                              '2021-03-10T18:15:54.000Z'
                                            ],
                           'Network1' => [
                                              'Not used',
                                              'Not used'
                                            ]
                         }
        }; 

##</code><code>##

foreach my $key (keys(%hash)) {

	foreach my net (keys %{ $hash{$key} }) {
		my $date_time = (sort @{ $ssoidmfadates{$key}{$net} })[-1];
		my @dt_dob1 = unpack("A4xA2xA2",$date_time);
	
		if (check_date(@dt_dob1)){
			print  "SSO ID: $key, Mfa Cat : $net , Valid: $date_time\n";
			} else { 
		   
		  print "Not used";
		   }
	}
}