diff --git a/pom.xml b/pom.xml
index 9fb8bdd6..4a00c145 100644
--- a/pom.xml
+++ b/pom.xml
@@ -4,7 +4,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>org.pamguard</groupId>
   <artifactId>Pamguard</artifactId>
-  <version>2.02.05a</version>
+  <version>2.02.06</version>
   <name>Pamguard Java12+</name>
   <description>Pamguard for Java 12+, using Maven to control dependcies</description>
 	<url>www.pamguard.org</url>
diff --git a/src/Filters/IIRFilterMethod.java b/src/Filters/IIRFilterMethod.java
index 44dd4c2f..bd902e69 100644
--- a/src/Filters/IIRFilterMethod.java
+++ b/src/Filters/IIRFilterMethod.java
@@ -313,6 +313,9 @@ public abstract class IIRFilterMethod extends FilterMethod {
 //		if (nOddOnes != 0) {
 			pole1 = pzPairs[i].getPole();
 			zero1 = pzPairs[i].getZero();
+			if (pole1 == null || zero1 == null) {
+				continue;
+			}
 			a1 = -zero1.real;
 			b1 = pole1.real;
 			doubleCoefficients[j+0] = a1;
diff --git a/src/PamController/PamguardVersionInfo.java b/src/PamController/PamguardVersionInfo.java
index 270b31df..68b68f42 100644
--- a/src/PamController/PamguardVersionInfo.java
+++ b/src/PamController/PamguardVersionInfo.java
@@ -31,12 +31,12 @@ public class PamguardVersionInfo {
 	 * Version number, major version.minorversion.sub-release.
 	 * Note: can't go higher than sub-release 'f'
 	 */
-	static public final String version = "2.02.05a";
+	static public final String version = "2.02.06";
 	
 	/**
 	 * Release date
 	 */
-	static public final String date = "11 November 2022";
+	static public final String date = "15 November 2022";
 	
 //	/**
 //	 * Release type - Beta or Core