diff --git a/pom.xml b/pom.xml
index 8246e7c..7c1e241 100644
--- a/pom.xml
+++ b/pom.xml
@@ -37,7 +37,7 @@
     </organization>
 
     <properties>
-        <revision>1.9.0-SNAPSHOT</revision>
+        <revision>1.9.0</revision>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
         <jts-core.version>1.19.0</jts-core.version>
@@ -78,7 +78,7 @@
                     <plugin>
                         <groupId>org.apache.maven.plugins</groupId>
                         <artifactId>maven-source-plugin</artifactId>
-                        <version>3.0.1</version>
+                        <version>3.2.1</version>
                         <executions>
                             <execution>
                                 <id>attach-sources</id>
@@ -93,7 +93,7 @@
                     <plugin>
                         <groupId>org.apache.maven.plugins</groupId>
                         <artifactId>maven-javadoc-plugin</artifactId>
-                        <version>3.1.1</version>
+                        <version>3.4.1</version>
                         <!-- doclint config removed for building with jdk < 8 (as in Travis) -->
                         <configuration>
                             <additionalOptions>-Xdoclint:none</additionalOptions>
@@ -112,7 +112,7 @@
                     <plugin>
                         <groupId>org.apache.maven.plugins</groupId>
                         <artifactId>maven-gpg-plugin</artifactId>
-                        <version>1.6</version>
+                        <version>3.0.1</version>
                         <executions>
                             <execution>
                                 <id>sign-artifacts</id>