diff --git a/pom.xml b/pom.xml
index 12851e6..90bae53 100644
--- a/pom.xml
+++ b/pom.xml
@@ -6,7 +6,7 @@
 
     <artifactId>GpxAndroidSdk</artifactId>
     <groupId>me.bvn13.sdk.android.gpx</groupId>
-    <version>1.0</version>
+    <version>1.1</version>
 
     <packaging>jar</packaging>
 
diff --git a/src/main/kotlin/me/bvn13/sdk/android/gpx/WptType.kt b/src/main/kotlin/me/bvn13/sdk/android/gpx/WptType.kt
index b565482..ed1e6d1 100644
--- a/src/main/kotlin/me/bvn13/sdk/android/gpx/WptType.kt
+++ b/src/main/kotlin/me/bvn13/sdk/android/gpx/WptType.kt
@@ -158,7 +158,7 @@ class WptType(
         require(magvar == null || magvar in 0.0..360.0) {
             "magvar must be degree in (0)..(360) in Double"
         }
-        require(dgpsid in 0..1023) {
+        require(dgpsid == null || dgpsid in 0..1023) {
             "dgpsid must be in 0..1023"
         }
     }