diff --git a/pom.xml b/pom.xml
index cfe3a7d..46fbf4f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -48,6 +48,7 @@
 
     <properties>
         <milo.version>0.2.0</milo.version>
+        <bouncycastle.version>[1.66,)</bouncycastle.version>
     </properties>
 
     <!-- OPC-DA -->
@@ -86,12 +87,12 @@
         <dependency>
             <groupId>org.bouncycastle</groupId>
             <artifactId>bcprov-jdk15on</artifactId>
-            <version>1.60</version>
+            <version>${bouncycastle.version}</version>
         </dependency>
         <dependency>
             <groupId>org.bouncycastle</groupId>
             <artifactId>bcpkix-jdk15on</artifactId>
-            <version>1.60</version>
+            <version>${bouncycastle.version}</version>
         </dependency>
 
         <!-- OPC-UA -->
@@ -115,13 +116,13 @@
         <dependency>
             <groupId>org.slf4j</groupId>
             <artifactId>slf4j-api</artifactId>
-            <version>1.7.12</version>
+            <version>1.7.36</version>
         </dependency>
 
         <dependency>
             <groupId>io.reactivex.rxjava2</groupId>
             <artifactId>rxjava</artifactId>
-            <version>2.2.4</version>
+            <version>2.2.21</version>
         </dependency>
 
         <!-- TESTING -->
@@ -129,14 +130,14 @@
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
-            <version>4.12</version>
+            <version>4.13.2</version>
             <scope>test</scope>
         </dependency>
 
         <dependency>
             <groupId>ch.qos.logback</groupId>
             <artifactId>logback-classic</artifactId>
-            <version>1.1.3</version>
+            <version>1.2.11</version>
             <scope>test</scope>
         </dependency>