diff --git a/dssi-vst-scanner.cpp b/dssi-vst-scanner.cpp
index 9ecc7c6..37ee5bb 100644
--- a/dssi-vst-scanner.cpp
+++ b/dssi-vst-scanner.cpp
@@ -133,6 +133,9 @@ WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, LPSTR cmdline, int cmdshow)
 	}
     }
 
+    int version = int(RemotePluginVersion * 1000);
+    write(targetfd, &version, sizeof(int));
+
     HINSTANCE libHandle = 0;
 
     std::vector<std::string> vstPath = Paths::getPath
@@ -206,14 +209,28 @@ WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, LPSTR cmdline, int cmdshow)
 	
 		struct stat st;
 		if (!stat(cacheFileName.c_str(), &st)) {
-		    haveCache = true;
-		} else {
+		    int testfd = open(cacheFileName.c_str(), O_RDONLY);
+		    if (testfd >= 0) {
+			int testVersion = 0;
+			if (read(testfd, &testVersion, sizeof(int)) == sizeof(int) &&
+			    testVersion == version) {
+			    haveCache = true;
+			} else {
+			    cerr << "dssi-vst-scanner: Cache version mismatch for file "
+				 << cacheFileName << " (" << testVersion << ", wanted "
+				 << version << ") - rewriting" << endl;
+			}
+			close(testfd);
+		    }
+		}
+		if (!haveCache) {
 		    if ((fd = open(cacheFileName.c_str(), O_WRONLY | O_CREAT, 0644)) < 0) {
 			cerr << "dssi-vst-scanner: Failed to open cache file " << cacheFileName;
 			perror(" for writing");
 			fd = targetfd;
 		    } else {
 			writingCache = true;
+			write(fd, &version, sizeof(int));
 		    }
 		}
 	    }
@@ -352,9 +369,15 @@ WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, LPSTR cmdline, int cmdshow)
 		    cerr << "dssi-vst-scanner: Failed to open cache file " << cacheFileName;
 		    perror("for reading");
 		} else {
-		    unsigned char c;
-		    while (read(fd, &c, 1) == 1) {
-			write(targetfd, &c, 1);
+		    int testVersion = 0;
+		    if (read(fd, &testVersion, sizeof(int)) != sizeof(int) ||
+			testVersion != version) {
+			cerr << "dssi-vst-scanner: Internal error: cache file " << cacheFileName << " verified earlier, but now fails version test (" << testVersion << " != " << version << ")" << endl;
+		    } else {
+			unsigned char c;
+			while (read(fd, &c, 1) == 1) {
+			    write(targetfd, &c, 1);
+			}
 		    }
 		    close(fd);
 		}
diff --git a/remoteplugin.h b/remoteplugin.h
index 848da49..b31ee49 100644
--- a/remoteplugin.h
+++ b/remoteplugin.h
@@ -8,7 +8,7 @@
 #ifndef REMOTE_PLUGIN_H
 #define REMOTE_PLUGIN_H
 
-static const float RemotePluginVersion = 0.8;
+static const float RemotePluginVersion = 0.9;
 
 enum RemotePluginDebugLevel {
     RemotePluginDebugNone,
diff --git a/remotevstclient.cpp b/remotevstclient.cpp
index 9ef953c..dbc6ab3 100644
--- a/remotevstclient.cpp
+++ b/remotevstclient.cpp
@@ -207,6 +207,12 @@ RemoteVSTClient::queryPlugins(std::vector<PluginRecord> &plugins)
 
     try {
 	char buffer[64];
+	int version = 0;
+
+	tryRead(fd, &version, sizeof(int));
+	if (version != int(RemotePluginVersion * 1000)) {
+	    throw ((std::string)"Plugin scanner version mismatch");
+	}
 
 	while (1) {