diff --git a/module-server/src/main/kotlin/de/twomartens/wahlrecht/property/ServiceProperties.kt b/module-server/src/main/kotlin/de/twomartens/wahlrecht/property/ServiceProperties.kt
index fe1905a..9f4825b 100644
--- a/module-server/src/main/kotlin/de/twomartens/wahlrecht/property/ServiceProperties.kt
+++ b/module-server/src/main/kotlin/de/twomartens/wahlrecht/property/ServiceProperties.kt
@@ -9,4 +9,4 @@ import java.time.ZoneId
 @RefreshScope
 @ConfigurationProperties(prefix = "de.twomartens.wahlrecht")
 @Schema(description = "Properties, to configure this Application")
-data class ServiceProperties @ConstructorBinding constructor(val defaultTimeZone: ZoneId, val greeting: String)
+data class ServiceProperties @ConstructorBinding constructor(var defaultTimeZone: ZoneId, var greeting: String)