Upgrade to Spring Framework 5.3.31.

Resolves #1388.

pom.xml

@@ -112,8 +112,8 @@
 		<slf4j.version>1.7.25</slf4j.version>
 		<smack.version>4.2.1</smack.version>
 		<soap-api.version>1.4.0</soap-api.version>
-		<spring.version>5.3.30</spring.version>
-		<spring-security.version>5.5.8</spring-security.version>
+		<spring.version>5.3.31</spring.version> <!-- TODO: Check spring-next-gen, spring-next-gen-snapshot profiles -->
+		<spring-security.version>5.5.8</spring-security.version> <!-- TODO: Check spring-next-gen, spring-next-gen-snapshot profiles -->
 		<stax.version>1.8.3</stax.version>
 		<sun-mail.version>1.6.0</sun-mail.version>
 		<woodstox.version>4.2.0</woodstox.version>
@@ -264,7 +264,7 @@
 		<profile>
 			<id>spring-buildsnapshot</id>
 			<properties>
-				<spring.version>5.3.31-SNAPSHOT</spring.version>
+				<spring.version>5.3.32-SNAPSHOT</spring.version>
 			</properties>
 		</profile>
 		<profile>