diff --git a/.liquibase/Data_alias/basic/2020.2.0/alter_ComunicationMedium_IdDatatype.xml b/.liquibase/Data_alias/basic/2020.2.0/alter_ComunicationMedium_IdDatatype.xml
new file mode 100644
index 0000000000000000000000000000000000000000..ec7089c3944c3472697003ce3c7671df8bf31fe8
--- /dev/null
+++ b/.liquibase/Data_alias/basic/2020.2.0/alter_ComunicationMedium_IdDatatype.xml
@@ -0,0 +1,48 @@
+<?xml version="1.1" encoding="UTF-8" standalone="no"?>
+<databaseChangeLog xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
+                   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.6.xsd">   
+    <!--*****
+        The data type has been changed by accident to CHAR(36) so let's change it back to VARCHAR(36) and update the data that is already persistant.
+        Tested on Apache Derby DB.
+    ******-->
+    <!--first: remove the index (if it's there) because on some dbms this prevents the column from changing/dropping-->
+    <changeSet author="j.goderbauer" id="763ea49e-8c9b-4262-9e2a-c59488358cd4">
+        <preConditions onFail="MARK_RAN">
+            <indexExists indexName="IDX_COMMUNICATION_MEDIUM_ID" tableName="COMMUNICATION"/>
+        </preConditions>
+        <dropIndex indexName="IDX_COMMUNICATION_MEDIUM_ID" tableName="COMMUNICATION" />
+    </changeSet>
+    <!--second: change the type, dependent on the dbms-->
+    <changeSet dbms="derby" author="j.goderbauer" id="c6e4a017-6e48-4238-80d7-41e2b210874d">
+        <sql>
+            ALTER TABLE COMMUNICATION ADD COLUMN MEDIUM_ID_NEW VARCHAR(36);
+            UPDATE COMMUNICATION SET MEDIUM_ID_NEW=MEDIUM_ID;
+            ALTER TABLE COMMUNICATION DROP COLUMN MEDIUM_ID;
+            RENAME COLUMN COMMUNICATION.MEDIUM_ID_NEW TO MEDIUM_ID;
+        </sql>
+    </changeSet>
+    <changeSet dbms="!derby" author="j.goderbauer" id="fbee4d8c-681d-4bea-b665-9fa951c3daa8">
+        <modifyDataType tableName="COMMUNICATION" columnName="MEDIUM_ID" newDataType="VARCHAR(36);"/>
+    </changeSet>
+    <!--third: update data that now contains the data with spaces at the end-->
+    <!--MS SQL supports the regular trim-function with  MS SQL 2017 or higher, so lets use the old ltrim/rtrim functions for better compability -->
+    <!--sauce: https://docs.microsoft.com/de-de/sql/t-sql/functions/trim-transact-sql?view=sql-server-ver15-->
+    <changeSet dbms="mssql" author="j.goderbauer" id="74b69edd-74f6-42c6-8164-e41614b47140">
+        <update tableName="COMMUNICATION">
+            <column name="MEDIUM_ID" valueComputed="ltrim(rtrim(MEDIUM_ID))" />
+            <where>MEDIUM_ID is not null</where>
+        </update>
+    </changeSet>
+    <changeSet dbms="!mssql" author="j.goderbauer" id="ee6466ce-ef57-44fd-b3c7-4e8fe305f25e">
+        <update tableName="COMMUNICATION">
+            <column name="MEDIUM_ID" valueComputed="trim(MEDIUM_ID)" />
+            <where>MEDIUM_ID is not null</where>
+        </update>
+    </changeSet>
+    <!--fourth: recreate the index with the original name-->
+    <changeSet author="j.goderbauer" id="071450d1-2cd6-487e-9b12-7f8b042f179c">
+        <createIndex indexName="IDX_COMMUNICATION_MEDIUM_ID" tableName="COMMUNICATION">
+            <column name="MEDIUM_ID"/>
+        </createIndex>
+    </changeSet>
+</databaseChangeLog>
diff --git a/.liquibase/Data_alias/basic/2020.2.0/changelog.xml b/.liquibase/Data_alias/basic/2020.2.0/changelog.xml
index 21311ae8dbdfb3ec388f1d2ef1b2c10ed79c1c13..7f2c9ff3251e91ea15d6b226d0d0b11b97004cdb 100644
--- a/.liquibase/Data_alias/basic/2020.2.0/changelog.xml
+++ b/.liquibase/Data_alias/basic/2020.2.0/changelog.xml
@@ -7,4 +7,5 @@
     <include relativeToChangelogFile="true" file="LeadimportMappingAssistant/changelog.xml"/>
     <include relativeToChangelogFile="true" file="optimizeIndizes.xml"/>
     <include relativeToChangelogFile="true" file="addNotificationStateKeywords/addNotificationStateKeyword.xml"/>
+    <include relativeToChangelogFile="true" file="alter_ComunicationMedium_IdDatatype.xml"/>
 </databaseChangeLog>
diff --git a/aliasDefinition/Data_alias/Data_alias.aod b/aliasDefinition/Data_alias/Data_alias.aod
index 9b001a59e78457253908bbb037b74c98570e5ece..a076f2356bd8dbb118ec3a04673e6c342a7f7b87 100644
--- a/aliasDefinition/Data_alias/Data_alias.aod
+++ b/aliasDefinition/Data_alias/Data_alias.aod
@@ -1208,7 +1208,7 @@
                 <name>MEDIUM_ID</name>
                 <dbName></dbName>
                 <primaryKey v="false" />
-                <columnType v="1" />
+                <columnType v="12" />
                 <size v="36" />
                 <scale v="0" />
                 <notNull v="false" />