2 files changed, 18 insertions, 13 deletions
diff --git a/api/src/main/java/org/semver/Delta.java b/api/src/main/java/org/semver/Delta.java
index e856bb2..ebb6b57 100755
--- a/api/src/main/java/org/semver/Delta.java
+++ b/api/src/main/java/org/semver/Delta.java
@@ -213,7 +213,7 @@ public final class Delta {
         if (current == null) {
             throw new IllegalArgumentException("null current");
         }
-        if (previous.compareTo(current) <= 0) {
+        if (current.compareTo(previous) <= 0) {
             throw new IllegalArgumentException("Current version <"+previous+"> must be more recent than previous version <"+current+">.");
         }
         //When in development public API is not considered stable
@@ -223,7 +223,7 @@ public final class Delta {
 
         //Current version must be superior or equals to inferred version
         final Version inferredVersion = infer(previous);
-        return inferredVersion.compareTo(current) >= 0;
+        return current.compareTo(inferredVersion) >= 0;
     }
     
 }
diff --git a/api/src/main/java/org/semver/Version.java b/api/src/main/java/org/semver/Version.java
index b4c76ee..e6c9abf 100755
--- a/api/src/main/java/org/semver/Version.java
+++ b/api/src/main/java/org/semver/Version.java
@@ -24,6 +24,7 @@ import javax.annotation.Nonnegative;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
+
 import org.apache.commons.lang.StringUtils;
 
 /**
@@ -159,20 +160,24 @@ public final class Version implements Comparable<Version> {
             return 0;
         }
 
-        if (other.major > this.major) {
-            return 1;
-        } else if (other.major == this.major) {
-            if (other.minor > this.minor) {
-                return 1;
-            } else if (other.minor == this.minor) {
-                if (other.patch > this.patch) {
-                    return 1;
+        if (this.major < other.major) {
+            return -1;
+        } else if (this.major == other.major) {
+            if (this.minor < other.minor) {
+                return -1;
+            } else if (this.minor == other.minor) {
+                if (this.patch < other.patch) {
+                    return -1;
+                } else if (this.special != null && other.special != null) {
+                    return this.special.compareTo(other.special);
                 } else if (other.special != null) {
-                    return other.special.compareTo(this.special);
-                }
+                    return -1;
+                } else if (this.special != null) {
+                    return 1;
+                } // else handled by previous equals check
             }
         }
-        return -1;
+        return 1;
     }
 
     @Override