diff --git a/include/ZeroTierOne.h b/include/ZeroTierOne.h
index 6f0517ba7..956fa304b 100644
--- a/include/ZeroTierOne.h
+++ b/include/ZeroTierOne.h
@@ -116,16 +116,6 @@ extern "C" {
  */
 #define ZT_MAX_PEER_NETWORK_PATHS 4
 
-/**
- * Feature flag: ZeroTier One was built to be thread-safe -- concurrent processXXX() calls are okay
- */
-#define ZT_FEATURE_FLAG_THREAD_SAFE 0x00000001
-
-/**
- * Feature flag: FIPS compliant build (not available yet, but reserved for future use if we ever do this)
- */
-#define ZT_FEATURE_FLAG_FIPS 0x00000002
-
 /**
  * Maximum number of hops in a ZeroTier circuit test
  *
@@ -1833,9 +1823,8 @@ void ZT_Node_backgroundThreadMain(ZT_Node *node);
  * @param major Result: major version
  * @param minor Result: minor version
  * @param revision Result: revision
- * @param featureFlags: Result: feature flag bitmap
  */
-void ZT_version(int *major,int *minor,int *revision,unsigned long *featureFlags);
+void ZT_version(int *major,int *minor,int *revision);
 
 #ifdef __cplusplus
 }
diff --git a/node/Node.cpp b/node/Node.cpp
index 5d534239d..698f23c32 100644
--- a/node/Node.cpp
+++ b/node/Node.cpp
@@ -1023,16 +1023,11 @@ void ZT_Node_backgroundThreadMain(ZT_Node *node)
 	} catch ( ... ) {}
 }
 
-void ZT_version(int *major,int *minor,int *revision,unsigned long *featureFlags)
+void ZT_version(int *major,int *minor,int *revision)
 {
 	if (major) *major = ZEROTIER_ONE_VERSION_MAJOR;
 	if (minor) *minor = ZEROTIER_ONE_VERSION_MINOR;
 	if (revision) *revision = ZEROTIER_ONE_VERSION_REVISION;
-	if (featureFlags) {
-		*featureFlags = (
-			ZT_FEATURE_FLAG_THREAD_SAFE
-		);
-	}
 }
 
 } // extern "C"