diff --git a/src/kcfg/expirycheckerconfigbase.kcfg b/src/kcfg/expirycheckerconfigbase.kcfg
index 5ea0d8f14..8231418aa 100644
--- a/src/kcfg/expirycheckerconfigbase.kcfg
+++ b/src/kcfg/expirycheckerconfigbase.kcfg
@@ -1,34 +1,42 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
   SPDX-License-Identifier: GPL-2.0-or-later
   SPDX-FileCopyrightText: 2023 g10 Code GmbH
   SPDX-FileContributor: Ingo Klöcker <dev@ingo-kloecker.de>
 -->
 <kcfg xmlns="http://www.kde.org/standards/kcfg/1.0"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.kde.org/standards/kcfg/1.0
       http://www.kde.org/standards/kcfg/1.0/kcfg.xsd" >
   <kcfgfile name="kleo-expirycheckerrc" />
     <group name="General">
     <entry key="ownKeyThresholdInDays" type="Int">
       <label>Threshold for own certificates</label>
       <whatsthis>This is the number of days you will be warned in advanced, if your own certificate is about to expire soon.</whatsthis>
       <default>30</default>
+      <min>-1</min>
+      <max>999</max>
     </entry>
     <entry key="otherKeyThresholdInDays" type="Int">
       <label>Threshold for other certificates</label>
       <whatsthis>This is the number of days you will be warned in advanced, if the certificate of another person that is used by you is about to expire soon.</whatsthis>
       <default>14</default>
+      <min>-1</min>
+      <max>999</max>
     </entry>
     <entry key="rootCertificateThresholdInDays" type="Int">
       <label>Threshold for root certificates</label>
       <whatsthis>This is the number of days you will be warned in advanced, if a root certificate that is used by you is about to expire soon.</whatsthis>
       <default>14</default>
+      <min>-1</min>
+      <max>999</max>
     </entry>
     <entry key="intermediateCertificateThresholdInDays" type="Int">
       <label>Threshold for intermediate certificates</label>
       <whatsthis>This is the number of days you will be warned in advanced, if an intermediate certificate that is used by you is about to expire soon.</whatsthis>
       <default>14</default>
+      <min>-1</min>
+      <max>999</max>
     </entry>
   </group>
 </kcfg>