diff --git a/backend/build.gradle b/backend/build.gradle
index df719116b..61add9d3a 100644
--- a/backend/build.gradle
+++ b/backend/build.gradle
@@ -2,7 +2,7 @@ import org.gradle.api.tasks.testing.logging.TestExceptionFormat
 import org.gradle.api.tasks.testing.logging.TestLogEvent
 
 plugins {
-    id 'org.springframework.boot' version '3.3.5'
+    id 'org.springframework.boot' version '3.4.0'
     id 'io.spring.dependency-management' version '1.1.6'
     // If kotlin version bumped, check if gradle version can be bumped as well 
     // Check here: https://kotlinlang.org/docs/gradle-configure-project.html#apply-the-plugin
@@ -36,7 +36,7 @@ dependencies {
     implementation "io.github.microutils:kotlin-logging-jvm:3.0.5"
     implementation "org.postgresql:postgresql:42.7.4"
     implementation "org.apache.commons:commons-csv:1.12.0"
-    implementation "org.springdoc:springdoc-openapi-starter-webmvc-ui:2.6.0"
+    implementation "org.springdoc:springdoc-openapi-starter-webmvc-ui:2.7.0"
     implementation "org.flywaydb:flyway-database-postgresql:10.21.0"
     implementation "org.jetbrains.exposed:exposed-spring-boot-starter:0.56.0"
     implementation "org.jetbrains.exposed:exposed-jdbc:0.56.0"
diff --git a/backend/src/main/kotlin/org/loculus/backend/utils/LocalDateJacksonModule.kt b/backend/src/main/kotlin/org/loculus/backend/utils/LocalDateJacksonModule.kt
new file mode 100644
index 000000000..be687bfc7
--- /dev/null
+++ b/backend/src/main/kotlin/org/loculus/backend/utils/LocalDateJacksonModule.kt
@@ -0,0 +1,29 @@
+package org.loculus.backend.utils
+
+import com.fasterxml.jackson.core.JsonGenerator
+import com.fasterxml.jackson.core.JsonParser
+import com.fasterxml.jackson.databind.DeserializationContext
+import com.fasterxml.jackson.databind.JsonDeserializer
+import com.fasterxml.jackson.databind.JsonSerializer
+import com.fasterxml.jackson.databind.SerializerProvider
+import com.fasterxml.jackson.databind.module.SimpleModule
+import kotlinx.datetime.LocalDate
+import org.springframework.context.annotation.Configuration
+
+@Configuration
+class LocalDateJacksonModule : SimpleModule() {
+    init {
+        addSerializer(LocalDate::class.java, LocalDateSerializer())
+        addDeserializer(LocalDate::class.java, LocalDateDeserializer())
+    }
+}
+
+class LocalDateSerializer : JsonSerializer<LocalDate>() {
+    override fun serialize(value: LocalDate, gen: JsonGenerator, serializers: SerializerProvider) {
+        gen.writeString(value.toString())
+    }
+}
+
+class LocalDateDeserializer : JsonDeserializer<LocalDate>() {
+    override fun deserialize(p: JsonParser, ctxt: DeserializationContext): LocalDate = LocalDate.parse(p.text)
+}