diff --git a/installer/data/mysql/atomicupdate/bug_40337.pl b/installer/data/mysql/atomicupdate/bug_40337.pl
new file mode 100755
index 0000000000..951097d56d
--- /dev/null
+++ b/installer/data/mysql/atomicupdate/bug_40337.pl
@@ -0,0 +1,32 @@
+use Modern::Perl;
+use Koha::Installer::Output qw(say_warning say_success say_info);
+
+return {
+    bug_number  => "40337",
+    description => "Define checkprevcheckout as ENUM",
+    up          => sub {
+        my ($args) = @_;
+        my ( $dbh, $out ) = @$args{qw(dbh out)};
+
+        $dbh->do(
+            q{
+            ALTER TABLE borrowers
+            MODIFY COLUMN `checkprevcheckout` enum('yes', 'no', 'inherit') NOT NULL DEFAULT 'inherit' COMMENT 'produce a warning for this patron if this item has previously been checked out to this patron if ''yes'', not if ''no'', defer to category setting if ''inherit''.'
+        }
+        );
+
+        $dbh->do(
+            q{
+            ALTER TABLE categories
+            MODIFY COLUMN `checkprevcheckout` enum('yes', 'no', 'inherit') NOT NULL DEFAULT 'inherit' COMMENT 'produce a warning for this patron category if this item has previously been checked out to this patron if ''yes'', not if ''no'', defer to syspref setting if ''inherit''.'
+        }
+        );
+
+        $dbh->do(
+            q{
+            ALTER TABLE deletedborrowers
+            MODIFY COLUMN `checkprevcheckout` enum('yes', 'no', 'inherit') NOT NULL DEFAULT 'inherit' COMMENT 'produce a warning for this patron if this item has previously been checked out to this patron if ''yes'', not if ''no'', defer to category setting if ''inherit''.'
+        }
+        );
+    },
+};
diff --git a/installer/data/mysql/kohastructure.sql b/installer/data/mysql/kohastructure.sql
index 5d7139383c..11018d4f7b 100644
--- a/installer/data/mysql/kohastructure.sql
+++ b/installer/data/mysql/kohastructure.sql
@@ -1598,7 +1598,7 @@ CREATE TABLE `borrowers` (
   `privacy` int(11) NOT NULL DEFAULT 1 COMMENT 'patron/borrower''s privacy settings related to their checkout history',
   `privacy_guarantor_fines` tinyint(1) NOT NULL DEFAULT 0 COMMENT 'controls if relatives can see this patron''s fines',
   `privacy_guarantor_checkouts` tinyint(1) NOT NULL DEFAULT 0 COMMENT 'controls if relatives can see this patron''s checkouts',
-  `checkprevcheckout` varchar(7) NOT NULL DEFAULT 'inherit' COMMENT 'produce a warning for this patron if this item has previously been checked out to this patron if ''yes'', not if ''no'', defer to category setting if ''inherit''.',
+  `checkprevcheckout` enum('yes', 'no', 'inherit') NOT NULL DEFAULT 'inherit' COMMENT 'produce a warning for this patron if this item has previously been checked out to this patron if ''yes'', not if ''no'', defer to category setting if ''inherit''.',
   `updated_on` timestamp NOT NULL DEFAULT current_timestamp() ON UPDATE current_timestamp() COMMENT 'time of last change could be useful for synchronization with external systems (among others)',
   `lastseen` datetime DEFAULT NULL COMMENT 'last time a patron has been seen (connected at the OPAC or staff interface)',
   `lang` varchar(25) NOT NULL DEFAULT 'default' COMMENT 'lang to use to send notices to this patron',
@@ -1808,7 +1808,7 @@ CREATE TABLE `categories` (
   `category_type` varchar(1) NOT NULL DEFAULT 'A' COMMENT 'type of Koha patron (Adult, Child, Professional, Organizational, Statistical, Staff)',
   `BlockExpiredPatronOpacActions` varchar(128) NOT NULL DEFAULT 'follow_syspref_BlockExpiredPatronOpacActions' COMMENT 'specific actions expired patrons of this category are blocked from performing or if the BlockExpiredPatronOpacActions system preference is to be followed',
   `default_privacy` enum('default','never','forever') NOT NULL DEFAULT 'default' COMMENT 'Default privacy setting for this patron category',
-  `checkprevcheckout` varchar(7) NOT NULL DEFAULT 'inherit' COMMENT 'produce a warning for this patron category if this item has previously been checked out to this patron if ''yes'', not if ''no'', defer to syspref setting if ''inherit''.',
+  `checkprevcheckout` enum('yes', 'no', 'inherit') NOT NULL DEFAULT 'inherit' COMMENT 'produce a warning for this patron category if this item has previously been checked out to this patron if ''yes'', not if ''no'', defer to syspref setting if ''inherit''.',
   `can_place_ill_in_opac` tinyint(1) NOT NULL DEFAULT 1 COMMENT 'can this patron category place interlibrary loan requests',
   `can_be_guarantee` tinyint(1) NOT NULL DEFAULT 0 COMMENT 'if patrons of this category can be guarantees',
   `reset_password` tinyint(1) DEFAULT NULL COMMENT 'if patrons of this category can do the password reset flow,',
@@ -2760,7 +2760,7 @@ CREATE TABLE `deletedborrowers` (
   `privacy` int(11) NOT NULL DEFAULT 1 COMMENT 'patron/borrower''s privacy settings related to their checkout history  KEY `borrowernumber` (`borrowernumber`),',
   `privacy_guarantor_fines` tinyint(1) NOT NULL DEFAULT 0 COMMENT 'controls if relatives can see this patron''s fines',
   `privacy_guarantor_checkouts` tinyint(1) NOT NULL DEFAULT 0 COMMENT 'controls if relatives can see this patron''s checkouts',
-  `checkprevcheckout` varchar(7) NOT NULL DEFAULT 'inherit' COMMENT 'produce a warning for this patron if this item has previously been checked out to this patron if ''yes'', not if ''no'', defer to category setting if ''inherit''.',
+  `checkprevcheckout` enum('yes', 'no', 'inherit') NOT NULL DEFAULT 'inherit' COMMENT 'produce a warning for this patron if this item has previously been checked out to this patron if ''yes'', not if ''no'', defer to category setting if ''inherit''.',
   `updated_on` timestamp NOT NULL DEFAULT current_timestamp() ON UPDATE current_timestamp() COMMENT 'time of last change could be useful for synchronization with external systems (among others)',
   `lastseen` datetime DEFAULT NULL COMMENT 'last time a patron has been seen (connected at the OPAC or staff interface)',
   `lang` varchar(25) NOT NULL DEFAULT 'default' COMMENT 'lang to use to send notices to this patron',