diff --git a/.drone.yml b/.drone.yml
index 2d45edb..8ad9e16 100644
--- a/.drone.yml
+++ b/.drone.yml
@@ -44,3 +44,37 @@ steps:
     when:
       branch:
         - master
+
+  - name: build 15.0 image
+    image: plugins/docker
+    settings:
+      context: 15.0/unit
+      dockerfile: 15.0/unit/Dockerfile
+      repo: eumau/nextcloud
+      tags:
+        - 15.0
+        - 15.0-unit
+      username:
+        from_secret: dockerhub_username
+      password:
+        from_secret: dockerhub_password
+    when:
+      branch:
+        - master
+
+  - name: build 14.0 image
+    image: plugins/docker
+    settings:
+      context: 14.0/unit
+      dockerfile: 14.0/unit/Dockerfile
+      repo: eumau/nextcloud
+      tags:
+        - 14.0
+        - 14.0-unit
+      username:
+        from_secret: dockerhub_username
+      password:
+        from_secret: dockerhub_password
+    when:
+      branch:
+        - master
diff --git a/14.0/unit/Dockerfile b/14.0/unit/Dockerfile
index 5daccec..88bf5c2 100644
--- a/14.0/unit/Dockerfile
+++ b/14.0/unit/Dockerfile
@@ -209,14 +209,15 @@ ENV LDAP_BASE_GROUPS=
 ENV LDAP_USER_FILTER_OBJECTCLASS=inetOrgPerson
 ENV LDAP_USER_FILTER=
 ENV LDAP_LOGIN_FILTER=
-ENV LDAP_GROUP_FILTER_OBJECTCLASS=organizationalRole
+ENV LDAP_GROUP_FILTER_OBJECTCLASS=groupOfUniqueNames
 ENV LDAP_GROUP_FILTER=
 ENV LDAP_GID_NUMBER=gidNumber
 ENV LDAP_USER_DISPLAY_NAME=cn
 ENV LDAP_USER_DISPLAY_NAME_2=
 ENV LDAP_GROUP_DISPLAY_NAME=cn
 ENV LDAP_EMAIL_ATTRIBUTE=mail
-ENV LDAP_GROUP_MEMBER_ASSOC_ATTR=memberUid
+ENV LDAP_GROUP_MEMBER_ASSOC_ATTR=uniqueMember
+ENV LDAP_EXPERT_USERNAME_ATTR=
 
 EXPOSE 9000 9001 9002 9003 9010 9011 9012 9013
 ENTRYPOINT ["/entrypoint.sh"]
diff --git a/14.0/unit/ldap_setup.sh b/14.0/unit/ldap_setup.sh
index 76024a9..7e9602b 100755
--- a/14.0/unit/ldap_setup.sh
+++ b/14.0/unit/ldap_setup.sh
@@ -17,25 +17,25 @@ php occ ldap:show-config s01 | grep -q 'Invalid configID' &&  {
     php occ ldap:create-empty-config
 }
 
-[[ -z ${LDAP_HOST} ]] || {
+[[ -z ${LDAP_HOST:+x} ]] || {
     php occ ldap:set-config s01 ldapHost ${LDAP_HOST}
     php occ ldap:set-config s01 ldapPort ${LDAP_PORT:-389}
 }
-[[ -z ${LDAP_BACKUP_HOST} ]] || {
+[[ -z ${LDAP_BACKUP_HOST:+x} ]] || {
     php occ ldap:set-config s01 ldapBackupHost ${LDAP_BACKUP_HOST}
     php occ ldap:set-config s01 ldapBackupPort ${LDAP_BACKUP_PORT:-389}
 }
 
 # credentials for accessing LDAP directory
-[[ -z ${LDAP_AGENT_NAME} ]] || {
+[[ -z ${LDAP_AGENT_NAME:+x} ]] || {
     php occ ldap:set-config s01 ldapAgentName ${LDAP_AGENT_NAME}
 }
-[[ -z ${LDAP_AGENT_PASSWORD} ]] || {
+[[ -z ${LDAP_AGENT_PASSWORD:+x} ]] || {
     php occ ldap:set-config s01 ldapAgentPassword ${LDAP_AGENT_PASSWORD}
 }
 
 # search base
-[[ -z ${LDAP_BASE} ]] || {
+[[ -z ${LDAP_BASE:+x} ]] || {
     php occ ldap:set-config s01 ldapBase ${LDAP_BASE}
     php occ ldap:set-config s01 ldapBaseUsers ${LDAP_BASE_USERS:-ou=People,${LDAP_BASE}}
     php occ ldap:set-config s01 ldapBaseGroups ${LDAP_BASE_GROUPS:-ou=Group,${LDAP_BASE}}
@@ -72,7 +72,7 @@ php occ ldap:set-config s01 ldapGroupFilter "${LDAP_GROUP_FILTER}"
 php occ ldap:set-config s01 ldapGidNumber "${LDAP_GID_NUMBER:-gidNumber}"
 
 php occ ldap:set-config s01 ldapUserDisplayName "${LDAP_USER_DISPLAY_NAME:-cn}"
-[[ -z ${LDAP_USER_DISPLAY_NAME_2} ]] || {
+[[ -z ${LDAP_USER_DISPLAY_NAME_2:+x} ]] || {
     php occ ldap:set-config s01 ldapUserDisplayName2 "${LDAP_USER_DISPLAY_NAME_2}"
 }
 php occ ldap:set-config s01 ldapGroupDisplayName "${LDAP_GROUP_DISPLAY_NAME:-cn}"
@@ -82,7 +82,11 @@ php occ ldap:set-config s01 ldapGroupDisplayName "${LDAP_GROUP_DISPLAY_NAME:-cn}
 # | ldapQuotaDefault              |             |
 
 php occ ldap:set-config s01 ldapEmailAttribute "${LDAP_EMAIL_ATTRIBUTE:-mail}"
-php occ ldap:set-config s01 ldapGroupMemberAssocAttr "${LDAP_GROUP_MEMBER_ASSOC_ATTR:-memberUid}"
+php occ ldap:set-config s01 ldapGroupMemberAssocAttr "${LDAP_GROUP_MEMBER_ASSOC_ATTR:-uniqueMember}"
+
+[[ -z ${LDAP_EXPERT_USERNAME_ATTR:+x} ]] || {
+    php occ ldap:set-config s01 ldapExpertUsernameAttr "${LDAP_EXPERT_USERNAME_ATTR}"
+}
 
 # | hasMemberOfFilterSupport      | 0           |
 # | homeFolderNamingRule          |             |
diff --git a/15.0/unit/Dockerfile b/15.0/unit/Dockerfile
index 5da9608..3ac383f 100644
--- a/15.0/unit/Dockerfile
+++ b/15.0/unit/Dockerfile
@@ -209,14 +209,15 @@ ENV LDAP_BASE_GROUPS=
 ENV LDAP_USER_FILTER_OBJECTCLASS=inetOrgPerson
 ENV LDAP_USER_FILTER=
 ENV LDAP_LOGIN_FILTER=
-ENV LDAP_GROUP_FILTER_OBJECTCLASS=organizationalRole
+ENV LDAP_GROUP_FILTER_OBJECTCLASS=groupOfUniqueNames
 ENV LDAP_GROUP_FILTER=
 ENV LDAP_GID_NUMBER=gidNumber
 ENV LDAP_USER_DISPLAY_NAME=cn
 ENV LDAP_USER_DISPLAY_NAME_2=
 ENV LDAP_GROUP_DISPLAY_NAME=cn
 ENV LDAP_EMAIL_ATTRIBUTE=mail
-ENV LDAP_GROUP_MEMBER_ASSOC_ATTR=memberUid
+ENV LDAP_GROUP_MEMBER_ASSOC_ATTR=uniqueMember
+ENV LDAP_EXPERT_USERNAME_ATTR=
 
 EXPOSE 9000 9001 9002 9003 9010 9011 9012 9013
 ENTRYPOINT ["/entrypoint.sh"]
diff --git a/15.0/unit/ldap_setup.sh b/15.0/unit/ldap_setup.sh
index 76024a9..7e9602b 100755
--- a/15.0/unit/ldap_setup.sh
+++ b/15.0/unit/ldap_setup.sh
@@ -17,25 +17,25 @@ php occ ldap:show-config s01 | grep -q 'Invalid configID' &&  {
     php occ ldap:create-empty-config
 }
 
-[[ -z ${LDAP_HOST} ]] || {
+[[ -z ${LDAP_HOST:+x} ]] || {
     php occ ldap:set-config s01 ldapHost ${LDAP_HOST}
     php occ ldap:set-config s01 ldapPort ${LDAP_PORT:-389}
 }
-[[ -z ${LDAP_BACKUP_HOST} ]] || {
+[[ -z ${LDAP_BACKUP_HOST:+x} ]] || {
     php occ ldap:set-config s01 ldapBackupHost ${LDAP_BACKUP_HOST}
     php occ ldap:set-config s01 ldapBackupPort ${LDAP_BACKUP_PORT:-389}
 }
 
 # credentials for accessing LDAP directory
-[[ -z ${LDAP_AGENT_NAME} ]] || {
+[[ -z ${LDAP_AGENT_NAME:+x} ]] || {
     php occ ldap:set-config s01 ldapAgentName ${LDAP_AGENT_NAME}
 }
-[[ -z ${LDAP_AGENT_PASSWORD} ]] || {
+[[ -z ${LDAP_AGENT_PASSWORD:+x} ]] || {
     php occ ldap:set-config s01 ldapAgentPassword ${LDAP_AGENT_PASSWORD}
 }
 
 # search base
-[[ -z ${LDAP_BASE} ]] || {
+[[ -z ${LDAP_BASE:+x} ]] || {
     php occ ldap:set-config s01 ldapBase ${LDAP_BASE}
     php occ ldap:set-config s01 ldapBaseUsers ${LDAP_BASE_USERS:-ou=People,${LDAP_BASE}}
     php occ ldap:set-config s01 ldapBaseGroups ${LDAP_BASE_GROUPS:-ou=Group,${LDAP_BASE}}
@@ -72,7 +72,7 @@ php occ ldap:set-config s01 ldapGroupFilter "${LDAP_GROUP_FILTER}"
 php occ ldap:set-config s01 ldapGidNumber "${LDAP_GID_NUMBER:-gidNumber}"
 
 php occ ldap:set-config s01 ldapUserDisplayName "${LDAP_USER_DISPLAY_NAME:-cn}"
-[[ -z ${LDAP_USER_DISPLAY_NAME_2} ]] || {
+[[ -z ${LDAP_USER_DISPLAY_NAME_2:+x} ]] || {
     php occ ldap:set-config s01 ldapUserDisplayName2 "${LDAP_USER_DISPLAY_NAME_2}"
 }
 php occ ldap:set-config s01 ldapGroupDisplayName "${LDAP_GROUP_DISPLAY_NAME:-cn}"
@@ -82,7 +82,11 @@ php occ ldap:set-config s01 ldapGroupDisplayName "${LDAP_GROUP_DISPLAY_NAME:-cn}
 # | ldapQuotaDefault              |             |
 
 php occ ldap:set-config s01 ldapEmailAttribute "${LDAP_EMAIL_ATTRIBUTE:-mail}"
-php occ ldap:set-config s01 ldapGroupMemberAssocAttr "${LDAP_GROUP_MEMBER_ASSOC_ATTR:-memberUid}"
+php occ ldap:set-config s01 ldapGroupMemberAssocAttr "${LDAP_GROUP_MEMBER_ASSOC_ATTR:-uniqueMember}"
+
+[[ -z ${LDAP_EXPERT_USERNAME_ATTR:+x} ]] || {
+    php occ ldap:set-config s01 ldapExpertUsernameAttr "${LDAP_EXPERT_USERNAME_ATTR}"
+}
 
 # | hasMemberOfFilterSupport      | 0           |
 # | homeFolderNamingRule          |             |
diff --git a/16.0/unit/Dockerfile b/16.0/unit/Dockerfile
index 5c57469..591ecb8 100644
--- a/16.0/unit/Dockerfile
+++ b/16.0/unit/Dockerfile
@@ -209,14 +209,15 @@ ENV LDAP_BASE_GROUPS=
 ENV LDAP_USER_FILTER_OBJECTCLASS=inetOrgPerson
 ENV LDAP_USER_FILTER=
 ENV LDAP_LOGIN_FILTER=
-ENV LDAP_GROUP_FILTER_OBJECTCLASS=organizationalRole
+ENV LDAP_GROUP_FILTER_OBJECTCLASS=groupOfUniqueNames
 ENV LDAP_GROUP_FILTER=
 ENV LDAP_GID_NUMBER=gidNumber
 ENV LDAP_USER_DISPLAY_NAME=cn
 ENV LDAP_USER_DISPLAY_NAME_2=
 ENV LDAP_GROUP_DISPLAY_NAME=cn
 ENV LDAP_EMAIL_ATTRIBUTE=mail
-ENV LDAP_GROUP_MEMBER_ASSOC_ATTR=memberUid
+ENV LDAP_GROUP_MEMBER_ASSOC_ATTR=uniqueMember
+ENV LDAP_EXPERT_USERNAME_ATTR=
 
 EXPOSE 9000 9001 9002 9003 9010 9011 9012 9013
 ENTRYPOINT ["/entrypoint.sh"]
diff --git a/16.0/unit/ldap_setup.sh b/16.0/unit/ldap_setup.sh
index 76024a9..7e9602b 100755
--- a/16.0/unit/ldap_setup.sh
+++ b/16.0/unit/ldap_setup.sh
@@ -17,25 +17,25 @@ php occ ldap:show-config s01 | grep -q 'Invalid configID' &&  {
     php occ ldap:create-empty-config
 }
 
-[[ -z ${LDAP_HOST} ]] || {
+[[ -z ${LDAP_HOST:+x} ]] || {
     php occ ldap:set-config s01 ldapHost ${LDAP_HOST}
     php occ ldap:set-config s01 ldapPort ${LDAP_PORT:-389}
 }
-[[ -z ${LDAP_BACKUP_HOST} ]] || {
+[[ -z ${LDAP_BACKUP_HOST:+x} ]] || {
     php occ ldap:set-config s01 ldapBackupHost ${LDAP_BACKUP_HOST}
     php occ ldap:set-config s01 ldapBackupPort ${LDAP_BACKUP_PORT:-389}
 }
 
 # credentials for accessing LDAP directory
-[[ -z ${LDAP_AGENT_NAME} ]] || {
+[[ -z ${LDAP_AGENT_NAME:+x} ]] || {
     php occ ldap:set-config s01 ldapAgentName ${LDAP_AGENT_NAME}
 }
-[[ -z ${LDAP_AGENT_PASSWORD} ]] || {
+[[ -z ${LDAP_AGENT_PASSWORD:+x} ]] || {
     php occ ldap:set-config s01 ldapAgentPassword ${LDAP_AGENT_PASSWORD}
 }
 
 # search base
-[[ -z ${LDAP_BASE} ]] || {
+[[ -z ${LDAP_BASE:+x} ]] || {
     php occ ldap:set-config s01 ldapBase ${LDAP_BASE}
     php occ ldap:set-config s01 ldapBaseUsers ${LDAP_BASE_USERS:-ou=People,${LDAP_BASE}}
     php occ ldap:set-config s01 ldapBaseGroups ${LDAP_BASE_GROUPS:-ou=Group,${LDAP_BASE}}
@@ -72,7 +72,7 @@ php occ ldap:set-config s01 ldapGroupFilter "${LDAP_GROUP_FILTER}"
 php occ ldap:set-config s01 ldapGidNumber "${LDAP_GID_NUMBER:-gidNumber}"
 
 php occ ldap:set-config s01 ldapUserDisplayName "${LDAP_USER_DISPLAY_NAME:-cn}"
-[[ -z ${LDAP_USER_DISPLAY_NAME_2} ]] || {
+[[ -z ${LDAP_USER_DISPLAY_NAME_2:+x} ]] || {
     php occ ldap:set-config s01 ldapUserDisplayName2 "${LDAP_USER_DISPLAY_NAME_2}"
 }
 php occ ldap:set-config s01 ldapGroupDisplayName "${LDAP_GROUP_DISPLAY_NAME:-cn}"
@@ -82,7 +82,11 @@ php occ ldap:set-config s01 ldapGroupDisplayName "${LDAP_GROUP_DISPLAY_NAME:-cn}
 # | ldapQuotaDefault              |             |
 
 php occ ldap:set-config s01 ldapEmailAttribute "${LDAP_EMAIL_ATTRIBUTE:-mail}"
-php occ ldap:set-config s01 ldapGroupMemberAssocAttr "${LDAP_GROUP_MEMBER_ASSOC_ATTR:-memberUid}"
+php occ ldap:set-config s01 ldapGroupMemberAssocAttr "${LDAP_GROUP_MEMBER_ASSOC_ATTR:-uniqueMember}"
+
+[[ -z ${LDAP_EXPERT_USERNAME_ATTR:+x} ]] || {
+    php occ ldap:set-config s01 ldapExpertUsernameAttr "${LDAP_EXPERT_USERNAME_ATTR}"
+}
 
 # | hasMemberOfFilterSupport      | 0           |
 # | homeFolderNamingRule          |             |
diff --git a/17.0/unit/Dockerfile b/17.0/unit/Dockerfile
index 86ba4fa..a1748a3 100644
--- a/17.0/unit/Dockerfile
+++ b/17.0/unit/Dockerfile
@@ -209,14 +209,15 @@ ENV LDAP_BASE_GROUPS=
 ENV LDAP_USER_FILTER_OBJECTCLASS=inetOrgPerson
 ENV LDAP_USER_FILTER=
 ENV LDAP_LOGIN_FILTER=
-ENV LDAP_GROUP_FILTER_OBJECTCLASS=organizationalRole
+ENV LDAP_GROUP_FILTER_OBJECTCLASS=groupOfUniqueNames
 ENV LDAP_GROUP_FILTER=
 ENV LDAP_GID_NUMBER=gidNumber
 ENV LDAP_USER_DISPLAY_NAME=cn
 ENV LDAP_USER_DISPLAY_NAME_2=
 ENV LDAP_GROUP_DISPLAY_NAME=cn
 ENV LDAP_EMAIL_ATTRIBUTE=mail
-ENV LDAP_GROUP_MEMBER_ASSOC_ATTR=memberUid
+ENV LDAP_GROUP_MEMBER_ASSOC_ATTR=uniqueMember
+ENV LDAP_EXPERT_USERNAME_ATTR=
 
 EXPOSE 9000 9001 9002 9003 9010 9011 9012 9013
 ENTRYPOINT ["/entrypoint.sh"]
diff --git a/17.0/unit/ldap_setup.sh b/17.0/unit/ldap_setup.sh
index 76024a9..7e9602b 100755
--- a/17.0/unit/ldap_setup.sh
+++ b/17.0/unit/ldap_setup.sh
@@ -17,25 +17,25 @@ php occ ldap:show-config s01 | grep -q 'Invalid configID' &&  {
     php occ ldap:create-empty-config
 }
 
-[[ -z ${LDAP_HOST} ]] || {
+[[ -z ${LDAP_HOST:+x} ]] || {
     php occ ldap:set-config s01 ldapHost ${LDAP_HOST}
     php occ ldap:set-config s01 ldapPort ${LDAP_PORT:-389}
 }
-[[ -z ${LDAP_BACKUP_HOST} ]] || {
+[[ -z ${LDAP_BACKUP_HOST:+x} ]] || {
     php occ ldap:set-config s01 ldapBackupHost ${LDAP_BACKUP_HOST}
     php occ ldap:set-config s01 ldapBackupPort ${LDAP_BACKUP_PORT:-389}
 }
 
 # credentials for accessing LDAP directory
-[[ -z ${LDAP_AGENT_NAME} ]] || {
+[[ -z ${LDAP_AGENT_NAME:+x} ]] || {
     php occ ldap:set-config s01 ldapAgentName ${LDAP_AGENT_NAME}
 }
-[[ -z ${LDAP_AGENT_PASSWORD} ]] || {
+[[ -z ${LDAP_AGENT_PASSWORD:+x} ]] || {
     php occ ldap:set-config s01 ldapAgentPassword ${LDAP_AGENT_PASSWORD}
 }
 
 # search base
-[[ -z ${LDAP_BASE} ]] || {
+[[ -z ${LDAP_BASE:+x} ]] || {
     php occ ldap:set-config s01 ldapBase ${LDAP_BASE}
     php occ ldap:set-config s01 ldapBaseUsers ${LDAP_BASE_USERS:-ou=People,${LDAP_BASE}}
     php occ ldap:set-config s01 ldapBaseGroups ${LDAP_BASE_GROUPS:-ou=Group,${LDAP_BASE}}
@@ -72,7 +72,7 @@ php occ ldap:set-config s01 ldapGroupFilter "${LDAP_GROUP_FILTER}"
 php occ ldap:set-config s01 ldapGidNumber "${LDAP_GID_NUMBER:-gidNumber}"
 
 php occ ldap:set-config s01 ldapUserDisplayName "${LDAP_USER_DISPLAY_NAME:-cn}"
-[[ -z ${LDAP_USER_DISPLAY_NAME_2} ]] || {
+[[ -z ${LDAP_USER_DISPLAY_NAME_2:+x} ]] || {
     php occ ldap:set-config s01 ldapUserDisplayName2 "${LDAP_USER_DISPLAY_NAME_2}"
 }
 php occ ldap:set-config s01 ldapGroupDisplayName "${LDAP_GROUP_DISPLAY_NAME:-cn}"
@@ -82,7 +82,11 @@ php occ ldap:set-config s01 ldapGroupDisplayName "${LDAP_GROUP_DISPLAY_NAME:-cn}
 # | ldapQuotaDefault              |             |
 
 php occ ldap:set-config s01 ldapEmailAttribute "${LDAP_EMAIL_ATTRIBUTE:-mail}"
-php occ ldap:set-config s01 ldapGroupMemberAssocAttr "${LDAP_GROUP_MEMBER_ASSOC_ATTR:-memberUid}"
+php occ ldap:set-config s01 ldapGroupMemberAssocAttr "${LDAP_GROUP_MEMBER_ASSOC_ATTR:-uniqueMember}"
+
+[[ -z ${LDAP_EXPERT_USERNAME_ATTR:+x} ]] || {
+    php occ ldap:set-config s01 ldapExpertUsernameAttr "${LDAP_EXPERT_USERNAME_ATTR}"
+}
 
 # | hasMemberOfFilterSupport      | 0           |
 # | homeFolderNamingRule          |             |
diff --git a/Dockerfile-unit.template b/Dockerfile-unit.template
index 9f0a048..e125052 100644
--- a/Dockerfile-unit.template
+++ b/Dockerfile-unit.template
@@ -208,14 +208,15 @@ ENV LDAP_BASE_GROUPS=
 ENV LDAP_USER_FILTER_OBJECTCLASS=inetOrgPerson
 ENV LDAP_USER_FILTER=
 ENV LDAP_LOGIN_FILTER=
-ENV LDAP_GROUP_FILTER_OBJECTCLASS=organizationalRole
+ENV LDAP_GROUP_FILTER_OBJECTCLASS=groupOfUniqueNames
 ENV LDAP_GROUP_FILTER=
 ENV LDAP_GID_NUMBER=gidNumber
 ENV LDAP_USER_DISPLAY_NAME=cn
 ENV LDAP_USER_DISPLAY_NAME_2=
 ENV LDAP_GROUP_DISPLAY_NAME=cn
 ENV LDAP_EMAIL_ATTRIBUTE=mail
-ENV LDAP_GROUP_MEMBER_ASSOC_ATTR=memberUid
+ENV LDAP_GROUP_MEMBER_ASSOC_ATTR=uniqueMember
+ENV LDAP_EXPERT_USERNAME_ATTR=
 
 EXPOSE 9000 9001 9002 9003 9010 9011 9012 9013
 ENTRYPOINT ["/entrypoint.sh"]
diff --git a/docker-ldap_setup.sh b/docker-ldap_setup.sh
index 76024a9..7e9602b 100755
--- a/docker-ldap_setup.sh
+++ b/docker-ldap_setup.sh
@@ -17,25 +17,25 @@ php occ ldap:show-config s01 | grep -q 'Invalid configID' &&  {
     php occ ldap:create-empty-config
 }
 
-[[ -z ${LDAP_HOST} ]] || {
+[[ -z ${LDAP_HOST:+x} ]] || {
     php occ ldap:set-config s01 ldapHost ${LDAP_HOST}
     php occ ldap:set-config s01 ldapPort ${LDAP_PORT:-389}
 }
-[[ -z ${LDAP_BACKUP_HOST} ]] || {
+[[ -z ${LDAP_BACKUP_HOST:+x} ]] || {
     php occ ldap:set-config s01 ldapBackupHost ${LDAP_BACKUP_HOST}
     php occ ldap:set-config s01 ldapBackupPort ${LDAP_BACKUP_PORT:-389}
 }
 
 # credentials for accessing LDAP directory
-[[ -z ${LDAP_AGENT_NAME} ]] || {
+[[ -z ${LDAP_AGENT_NAME:+x} ]] || {
     php occ ldap:set-config s01 ldapAgentName ${LDAP_AGENT_NAME}
 }
-[[ -z ${LDAP_AGENT_PASSWORD} ]] || {
+[[ -z ${LDAP_AGENT_PASSWORD:+x} ]] || {
     php occ ldap:set-config s01 ldapAgentPassword ${LDAP_AGENT_PASSWORD}
 }
 
 # search base
-[[ -z ${LDAP_BASE} ]] || {
+[[ -z ${LDAP_BASE:+x} ]] || {
     php occ ldap:set-config s01 ldapBase ${LDAP_BASE}
     php occ ldap:set-config s01 ldapBaseUsers ${LDAP_BASE_USERS:-ou=People,${LDAP_BASE}}
     php occ ldap:set-config s01 ldapBaseGroups ${LDAP_BASE_GROUPS:-ou=Group,${LDAP_BASE}}
@@ -72,7 +72,7 @@ php occ ldap:set-config s01 ldapGroupFilter "${LDAP_GROUP_FILTER}"
 php occ ldap:set-config s01 ldapGidNumber "${LDAP_GID_NUMBER:-gidNumber}"
 
 php occ ldap:set-config s01 ldapUserDisplayName "${LDAP_USER_DISPLAY_NAME:-cn}"
-[[ -z ${LDAP_USER_DISPLAY_NAME_2} ]] || {
+[[ -z ${LDAP_USER_DISPLAY_NAME_2:+x} ]] || {
     php occ ldap:set-config s01 ldapUserDisplayName2 "${LDAP_USER_DISPLAY_NAME_2}"
 }
 php occ ldap:set-config s01 ldapGroupDisplayName "${LDAP_GROUP_DISPLAY_NAME:-cn}"
@@ -82,7 +82,11 @@ php occ ldap:set-config s01 ldapGroupDisplayName "${LDAP_GROUP_DISPLAY_NAME:-cn}
 # | ldapQuotaDefault              |             |
 
 php occ ldap:set-config s01 ldapEmailAttribute "${LDAP_EMAIL_ATTRIBUTE:-mail}"
-php occ ldap:set-config s01 ldapGroupMemberAssocAttr "${LDAP_GROUP_MEMBER_ASSOC_ATTR:-memberUid}"
+php occ ldap:set-config s01 ldapGroupMemberAssocAttr "${LDAP_GROUP_MEMBER_ASSOC_ATTR:-uniqueMember}"
+
+[[ -z ${LDAP_EXPERT_USERNAME_ATTR:+x} ]] || {
+    php occ ldap:set-config s01 ldapExpertUsernameAttr "${LDAP_EXPERT_USERNAME_ATTR}"
+}
 
 # | hasMemberOfFilterSupport      | 0           |
 # | homeFolderNamingRule          |             |