diff --git a/ctldap.example.config b/ctldap.example.config
index 5a74b3d..c70cbe8 100644
--- a/ctldap.example.config
+++ b/ctldap.example.config
@@ -1,7 +1,10 @@
 ; Add debug infos to log
 debug=false
+
 ; This is required for clients using lowercase DNs, e.g. ownCloud/nextCloud
 dn_lower_case=true
+; This is required for clients that need lowercase email addresses, e.g. Seafile
+email_lower_case=true
 
 ; LDAP admin user, can be a "virtual" root user or a ChurchTools user name (virtual root is recommended!)
 ldap_user=root
@@ -37,7 +40,8 @@ cache_lifetime=10000
 ; Define the sites here. For each site please enter one section.
 ; The section title has to be in the format sites.<ldap_base_dn>, e.g. "sites.foobar",
 ;   where foobar is the organisation, as in the instance foobar.church.tools .
-; dn_lower_case is optional.
+; dn_lower_case is optional, if not specified, the default value will be taken from the config above
+; email_lower_case is optional, if not specified, the default value will be taken from the config above
 ; If ldap_base_dn is set above, the setting above are treated as an additional site.
 
 ;[sites.XXXXXXXXXXXXXXXXXXXX]
@@ -45,4 +49,5 @@ cache_lifetime=10000
 ;ct_uri=https://XXXXXXXXXXXXXXXXXXXX.church.tools/
 ;api_user=XXXXXXXXXXXXXXXXXXXX
 ;api_password=XXXXXXXXXXXXXXXXXXXX
-;dn_lower_case=true
\ No newline at end of file
+;dn_lower_case=true
+;email_lower_case=true
\ No newline at end of file
diff --git a/ctldap.js b/ctldap.js
index 0278f8c..f86fe8b 100644
--- a/ctldap.js
+++ b/ctldap.js
@@ -15,7 +15,6 @@ var path = require('path');
 var config = ini.parse(fs.readFileSync(path.resolve(__dirname, 'ctldap.config'), 'utf-8'));
 if (config.debug) {
   console.log("Debug mode enabled, expect lots of output!");
-  console.dir(config);
 }
 
 if (config.ldap_base_dn) {
@@ -48,6 +47,15 @@ Object.keys(config.sites).map(function(sitename, index) {
       return s;
     }
   }
+  if (site.email_lower_case || ((site.email_lower_case === undefined) && config.email_lower_case)) {
+    site.compatTransformEmail = function (s) {
+      return s ? s.toLowerCase() : s;
+    }
+  } else {
+    site.compatTransformEmail = function (s) {
+      return s;
+    }
+  }
   if (site.ct_uri.slice(-1) !== "/") {
     site.ct_uri += "/";
   }
@@ -204,8 +212,8 @@ function requestUsers (req, res, next) {
             postalCode: v.plz,
             l: v.ort,
             sn: v.name,
-            email: v.email,
-            mail: v.email,
+            email: site.compatTransformEmail(v.email),
+            mail: site.compatTransformEmail(v.email),
             objectclass: ['CTPerson'],
             memberof: (results.userGroups[v.id] || []).map(function (cn) {
               return site.compatTransform(site.fnGroupDn({ cn: cn }));