diff --git a/C4/Circulation.pm b/C4/Circulation.pm
index cc4a95a3ea..67a986b417 100644
--- a/C4/Circulation.pm
+++ b/C4/Circulation.pm
@@ -1241,14 +1241,14 @@ sub checkHighHolds {
         my $issuedate = dt_from_string();
 
         my $itype = $item_object->effective_itemtype;
-        my $useDaysMode_value = Koha::CirculationRules->get_useDaysMode_effective_value(
+        my $daysmode = Koha::CirculationRules->get_effective_daysmode(
             {
                 categorycode => $borrower->{categorycode},
                 itemtype     => $itype,
                 branchcode   => $branchcode,
             }
         );
-        my $calendar = Koha::Calendar->new( branchcode => $branchcode, days_mode => $useDaysMode_value );
+        my $calendar = Koha::Calendar->new( branchcode => $branchcode, days_mode => $daysmode );
 
         my $orig_due = C4::Circulation::CalcDateDue( $issuedate, $itype, $branchcode, $borrower );
 
@@ -3583,7 +3583,7 @@ sub updateWrongTransfer {
 $newdatedue = CalcDateDue($startdate,$itemtype,$branchcode,$borrower);
 
 this function calculates the due date given the start date and configured circulation rules,
-checking against the holidays calendar as per the useDaysMode circulation rule.
+checking against the holidays calendar as per the daysmode circulation rule.
 C<$startdate>   = DateTime object representing start date of loan period (assumed to be today)
 C<$itemtype>  = itemtype code of item in question
 C<$branch>  = location whose calendar to use
@@ -3617,7 +3617,7 @@ sub CalcDateDue {
     }
 
 
-    my $useDaysMode_value = Koha::CirculationRules->get_useDaysMode_effective_value(
+    my $daysmode = Koha::CirculationRules->get_effective_daysmode(
         {
             categorycode => $borrower->{categorycode},
             itemtype     => $itemtype,
@@ -3626,7 +3626,7 @@ sub CalcDateDue {
     );
 
     # calculate the datedue as normal
-    if ( $useDaysMode_value eq 'Days' )
+    if ( $daysmode eq 'Days' )
     {    # ignoring calendar
         if ( $loanlength->{lengthunit} eq 'hours' ) {
             $datedue->add( hours => $loanlength->{$length_key} );
@@ -3643,7 +3643,7 @@ sub CalcDateDue {
         else { # days
             $dur = DateTime::Duration->new( days => $loanlength->{$length_key});
         }
-        my $calendar = Koha::Calendar->new( branchcode => $branch, days_mode => $useDaysMode_value );
+        my $calendar = Koha::Calendar->new( branchcode => $branch, days_mode => $daysmode );
         $datedue = $calendar->addDate( $datedue, $dur, $loanlength->{lengthunit} );
         if ($loanlength->{lengthunit} eq 'days') {
             $datedue->set_hour(23);
@@ -3681,8 +3681,8 @@ sub CalcDateDue {
                 $datedue = $expiry_dt->clone->set_time_zone( C4::Context->tz );
             }
         }
-        if ( $useDaysMode_value ne 'Days' ) {
-          my $calendar = Koha::Calendar->new( branchcode => $branch, days_mode => $useDaysMode_value );
+        if ( $daysmode ne 'Days' ) {
+          my $calendar = Koha::Calendar->new( branchcode => $branch, days_mode => $daysmode );
           if ( $calendar->is_holiday($datedue) ) {
               # Don't return on a closed day
               $datedue = $calendar->prev_open_days( $datedue, 1 );
diff --git a/Koha/Checkouts.pm b/Koha/Checkouts.pm
index 1f33cb1d81..2ade76e20e 100644
--- a/Koha/Checkouts.pm
+++ b/Koha/Checkouts.pm
@@ -48,14 +48,14 @@ sub calculate_dropbox_date {
     my $userenv    = C4::Context->userenv;
     my $branchcode = $userenv->{branch} // q{};
 
-    my $useDaysMode_value = Koha::CirculationRules->get_useDaysMode_effective_value(
+    my $daysmode = Koha::CirculationRules->get_effective_daysmode(
         {
             categorycode => undef,
             itemtype     => undef,
             branchcode   => $branchcode,
         }
     );
-    my $calendar     = Koha::Calendar->new( branchcode => $branchcode, days_mode => $useDaysMode_value );
+    my $calendar     = Koha::Calendar->new( branchcode => $branchcode, days_mode => $daysmode );
     my $today        = dt_from_string;
     my $dropbox_date = $calendar->addDate( $today, -1 );
 
diff --git a/Koha/CirculationRules.pm b/Koha/CirculationRules.pm
index 17e7674130..790f30498d 100644
--- a/Koha/CirculationRules.pm
+++ b/Koha/CirculationRules.pm
@@ -109,7 +109,7 @@ our $RULE_KINDS = {
     issuelength => {
         scope => [ 'branchcode', 'categorycode', 'itemtype' ],
     },
-    useDaysMode => {
+    daysmode => {
         scope => [ 'branchcode', 'categorycode', 'itemtype' ],
     },
     lengthunit => {
@@ -490,32 +490,32 @@ sub guess_article_requestable_itemtypes {
     return $res;
 }
 
-=head3 get_useDaysMode_effective_value
+=head3 get_daysmode_effective_value
 
-Return the value for useDaysMode defined in the circulation rules.
+Return the value for daysmode defined in the circulation rules.
 If not defined (or empty string), the value of the system preference useDaysMode is returned
 
 =cut
 
-sub get_useDaysMode_effective_value {
+sub get_effective_daysmode {
     my ( $class, $params ) = @_;
 
     my $categorycode     = $params->{categorycode};
     my $itemtype         = $params->{itemtype};
     my $branchcode       = $params->{branchcode};
 
-    my $useDaysMode_rule = $class->get_effective_rule(
+    my $daysmode_rule = $class->get_effective_rule(
         {
             categorycode => $categorycode,
             itemtype     => $itemtype,
             branchcode   => $branchcode,
-            rule_name    => 'useDaysMode',
+            rule_name    => 'daysmode',
         }
     );
 
-    return ( defined($useDaysMode_rule)
-          and $useDaysMode_rule->rule_value ne '' )
-      ? $useDaysMode_rule->rule_value
+    return ( defined($daysmode_rule)
+          and $daysmode_rule->rule_value ne '' )
+      ? $daysmode_rule->rule_value
       : C4::Context->preference('useDaysMode');
 
 }
diff --git a/Koha/Hold.pm b/Koha/Hold.pm
index 700c85572a..8969e32839 100644
--- a/Koha/Hold.pm
+++ b/Koha/Hold.pm
@@ -184,14 +184,14 @@ sub set_waiting {
 
     if ( C4::Context->preference("ExcludeHolidaysFromMaxPickUpDelay") ) {
         my $itemtype = $self->item ? $self->item->effective_itemtype : $self->biblio->itemtype;
-        my $useDaysMode_value = Koha::CirculationRules->get_useDaysMode_effective_value(
+        my $daysmode = Koha::CirculationRules->get_effective_daysmode(
             {
                 categorycode => $self->borrower->categorycode,
                 itemtype     => $itemtype,
                 branchcode   => $self->branchcode,
             }
         );
-        my $calendar = Koha::Calendar->new( branchcode => $self->branchcode, days_mode => $useDaysMode_value );
+        my $calendar = Koha::Calendar->new( branchcode => $self->branchcode, days_mode => $daysmode );
 
         $expirationdate = $calendar->days_forward( dt_from_string(), $max_pickup_delay );
     }
diff --git a/admin/smart-rules.pl b/admin/smart-rules.pl
index a76cbbac3c..20da1b1d6d 100755
--- a/admin/smart-rules.pl
+++ b/admin/smart-rules.pl
@@ -94,7 +94,7 @@ if ($op eq 'delete') {
                 chargeperiod                     => undef,
                 chargeperiod_charge_at           => undef,
                 issuelength                      => undef,
-                useDaysMode                      => undef,
+                daysmode                         => undef,
                 lengthunit                       => undef,
                 hardduedate                      => undef,
                 hardduedatecompare               => undef,
@@ -279,7 +279,7 @@ elsif ($op eq 'add') {
     my $onshelfholds     = $input->param('onshelfholds') || 0;
     my $issuelength  = $input->param('issuelength');
     $issuelength = $issuelength eq q{} ? undef : $issuelength;
-    my $useDaysMode = $input->param('useDaysMode');
+    my $daysmode = $input->param('daysmode');
     my $lengthunit  = $input->param('lengthunit');
     my $hardduedate = $input->param('hardduedate') || undef;
     $hardduedate = eval { dt_from_string( $input->param('hardduedate') ) } if ( $hardduedate );
@@ -305,7 +305,7 @@ elsif ($op eq 'add') {
         chargeperiod                  => $chargeperiod,
         chargeperiod_charge_at        => $chargeperiod_charge_at,
         issuelength                   => $issuelength,
-        useDaysMode                   => $useDaysMode,
+        daysmode                      => $daysmode,
         lengthunit                    => $lengthunit,
         hardduedate                   => $hardduedate,
         hardduedatecompare            => $hardduedatecompare,
diff --git a/koha-tmpl/intranet-tmpl/prog/en/modules/admin/smart-rules.tt b/koha-tmpl/intranet-tmpl/prog/en/modules/admin/smart-rules.tt
index dcd53bbb13..ce3531596d 100644
--- a/koha-tmpl/intranet-tmpl/prog/en/modules/admin/smart-rules.tt
+++ b/koha-tmpl/intranet-tmpl/prog/en/modules/admin/smart-rules.tt
@@ -131,7 +131,7 @@
                         [% SET maxissueqty = all_rules.$c.$i.maxissueqty %]
                         [% SET maxonsiteissueqty = all_rules.$c.$i.maxonsiteissueqty %]
                         [% SET issuelength = all_rules.$c.$i.issuelength %]
-                        [% SET useDaysMode = all_rules.$c.$i.useDaysMode %]
+                        [% SET daysmode = all_rules.$c.$i.daysmode %]
                         [% SET lengthunit = all_rules.$c.$i.lengthunit %]
                         [% SET hardduedate = all_rules.$c.$i.hardduedate %]
                         [% SET hardduedatecompare = all_rules.$c.$i.hardduedatecompare %]
@@ -158,7 +158,7 @@
                         [% SET article_requests = all_rules.$c.$i.article_requests %]
                         [% SET rentaldiscount = all_rules.$c.$i.rentaldiscount %]
 
-                        [% SET show_rule = maxissueqty || maxonsiteissueqty || issuelength || useDaysMode || lengthunit || hardduedate || hardduedatebefore || hardduedateexact || fine || chargeperiod || chargeperiod_charge_at || firstremind || overduefinescap || cap_fine_to_replacement_price || finedays || maxsuspensiondays || suspension_chargeperiod || renewalsallowed || renewalsallowed || norenewalbefore || auto_renew || no_auto_renewal_after || no_auto_renewal_after_hard_limit || reservesallowed || holds_per_day || holds_per_record || onshelfholds || opacitemholds || article_requests || article_requests %]
+                        [% SET show_rule = maxissueqty || maxonsiteissueqty || issuelength || daysmode || lengthunit || hardduedate || hardduedatebefore || hardduedateexact || fine || chargeperiod || chargeperiod_charge_at || firstremind || overduefinescap || cap_fine_to_replacement_price || finedays || maxsuspensiondays || suspension_chargeperiod || renewalsallowed || renewalsallowed || norenewalbefore || auto_renew || no_auto_renewal_after || no_auto_renewal_after_hard_limit || reservesallowed || holds_per_day || holds_per_record || onshelfholds || opacitemholds || article_requests || article_requests %]
                         [% IF show_rule %]
                             [% SET row_count = row_count + 1 %]
                             <tr row_countd="row_[% row_count | html %]">
@@ -201,7 +201,7 @@
                                     </td>
                                     <td>[% issuelength | html %]</td>
                                     <td>
-                                        [% SWITCH useDaysMode %]
+                                        [% SWITCH daysmode %]
                                         [% CASE 'Calendar' %]<span title="Use the calendar to skip days the library is closed">Calendar</span>
                                         [% CASE 'Datedue' %]<span title="Use the calendar to push the due date to the next open day">Datedue</span>
                                         [% CASE 'Days' %]<span title="Ignore the calendar">Days</span>
@@ -346,7 +346,7 @@
                     <td><input type="text" name="maxonsiteissueqty" id="maxonsiteissueqty" size="3" /></td>
                     <td><input type="text" name="issuelength" id="issuelength" size="3" /> </td>
                     <td>
-                        <select name="useDaysMode" id="useDaysMode">
+                        <select name="daysmode" id="daysmode">
                             <option value="">Default</option>
                             <option value="Calendar">Calendar</option>
                             <option value="Datedue">Datedue</option>
diff --git a/misc/cronjobs/thirdparty/TalkingTech_itiva_outbound.pl b/misc/cronjobs/thirdparty/TalkingTech_itiva_outbound.pl
index cbab04947d..dd4d2f9ff2 100755
--- a/misc/cronjobs/thirdparty/TalkingTech_itiva_outbound.pl
+++ b/misc/cronjobs/thirdparty/TalkingTech_itiva_outbound.pl
@@ -333,7 +333,7 @@ sub GetWaitingHolds {
     my @results;
     while ( my $issue = $sth->fetchrow_hashref() ) {
         my $item = Koha::Items->find({ barcode => $issue->{barcode} });
-        my $useDaysMode_value = Koha::CirculationRules->get_useDaysMode_effective_value(
+        my $daysmode = Koha::CirculationRules->get_effective_daysmode(
             {
                 categorycode => $issue->{categorycode},
                 itemtype     => $item->effective_itemtype,
@@ -341,7 +341,7 @@ sub GetWaitingHolds {
             }
         );
 
-        my $calendar = Koha::Calendar->new( branchcode => $issue->{'site'}, days_mode => $useDaysMode_value );
+        my $calendar = Koha::Calendar->new( branchcode => $issue->{'site'}, days_mode => $daysmode );
 
         my $waiting_date = dt_from_string( $issue->{waitingdate}, 'sql' );
         my $pickup_date = $waiting_date->clone->add( days => $pickupdelay );
diff --git a/t/db_dependent/Koha/CirculationRules.t b/t/db_dependent/Koha/CirculationRules.t
index d2868d26c8..f24542e2b6 100644
--- a/t/db_dependent/Koha/CirculationRules.t
+++ b/t/db_dependent/Koha/CirculationRules.t
@@ -284,7 +284,7 @@ subtest 'get_onshelfholds_policy() tests' => sub {
     $schema->storage->txn_rollback;
 };
 
-subtest 'get_useDaysMode_effective_value' => sub {
+subtest 'get_effective_daysmode' => sub {
     plan tests => 4;
 
     $schema->storage->txn_begin;
@@ -293,13 +293,13 @@ subtest 'get_useDaysMode_effective_value' => sub {
     my $item_2 = $builder->build_sample_item();
 
     my $circ_rules =
-      Koha::CirculationRules->search( { rule_name => 'useDaysMode' } )->delete;
+      Koha::CirculationRules->search( { rule_name => 'daysmode' } )->delete;
 
     # Default value 'Datedue' at pref level
     t::lib::Mocks::mock_preference( 'useDaysMode', 'Datedue' );
 
     is(
-        Koha::CirculationRules->get_useDaysMode_effective_value(
+        Koha::CirculationRules->get_effective_daysmode(
             {
                 categorycode => undef,
                 itemtype     => $item_1->effective_itemtype,
@@ -307,7 +307,7 @@ subtest 'get_useDaysMode_effective_value' => sub {
             }
         ),
         'Datedue',
-        'useDaysMode default to pref value if the rule does not exist'
+        'daysmode default to pref value if the rule does not exist'
     );
 
     Koha::CirculationRules->set_rule(
@@ -315,7 +315,7 @@ subtest 'get_useDaysMode_effective_value' => sub {
             branchcode   => '*',
             categorycode => '*',
             itemtype     => '*',
-            rule_name    => 'useDaysMode',
+            rule_name    => 'daysmode',
             rule_value   => 'Calendar',
         }
     );
@@ -324,13 +324,13 @@ subtest 'get_useDaysMode_effective_value' => sub {
             branchcode   => '*',
             categorycode => '*',
             itemtype     => $item_1->effective_itemtype,
-            rule_name    => 'useDaysMode',
+            rule_name    => 'daysmode',
             rule_value   => 'Days',
         }
     );
 
     is(
-        Koha::CirculationRules->get_useDaysMode_effective_value(
+        Koha::CirculationRules->get_effective_daysmode(
             {
                 categorycode => undef,
                 itemtype     => $item_1->effective_itemtype,
@@ -338,10 +338,10 @@ subtest 'get_useDaysMode_effective_value' => sub {
             }
         ),
         'Days',
-        "useDaysMode for item_1 is the specific rule"
+        "daysmode for item_1 is the specific rule"
     );
     is(
-        Koha::CirculationRules->get_useDaysMode_effective_value(
+        Koha::CirculationRules->get_effective_daysmode(
             {
                 categorycode => undef,
                 itemtype     => $item_2->effective_itemtype,
@@ -349,7 +349,7 @@ subtest 'get_useDaysMode_effective_value' => sub {
             }
         ),
         'Calendar',
-        "useDaysMode for item_2 is the one defined for the default circ rule"
+        "daysmode for item_2 is the one defined for the default circ rule"
     );
 
     Koha::CirculationRules->set_rule(
@@ -357,13 +357,13 @@ subtest 'get_useDaysMode_effective_value' => sub {
             branchcode   => '*',
             categorycode => '*',
             itemtype     => $item_2->effective_itemtype,
-            rule_name    => 'useDaysMode',
+            rule_name    => 'daysmode',
             rule_value   => '',
         }
     );
 
     is(
-        Koha::CirculationRules->get_useDaysMode_effective_value(
+        Koha::CirculationRules->get_effective_daysmode(
             {
                 categorycode => undef,
                 itemtype     => $item_2->effective_itemtype,
@@ -371,7 +371,7 @@ subtest 'get_useDaysMode_effective_value' => sub {
             }
         ),
         'Datedue',
-        'useDaysMode default to pref value if the rule exists but set to""'
+        'daysmode default to pref value if the rule exists but set to""'
     );
 
     $schema->storage->txn_rollback;