diff --git a/README.md b/README.md
index 7624f4e..472d1b9 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,10 @@ Pull or download the `master` branch
 Then to produce a `lczero-client` executable:
 `go build lc0_main.go` for the `lc0` client
 
+If you get
+`.\lc0_main.go:1048:5: undefined: chess.GetLibraryVersion`
+you have a cached old version of Tilps/chess and need to run the Pre-reqs again.
+
 # Running
 
 First copy the `lc0` executable into the same folder as the `lczero-client` executable.
@@ -52,4 +56,4 @@ Building the client for each platform:
 GOOS=windows GOARCH=amd64 go build -o lczero-client.exe
 GOOS=darwin GOARCH=amd64 go build -o lczero-client_mac
 GOOS=linux GOARCH=amd64 go build -o lczero-client_linux
-```
+```
\ No newline at end of file
diff --git a/lc0_main.go b/lc0_main.go
index 59505c2..54521a1 100644
--- a/lc0_main.go
+++ b/lc0_main.go
@@ -1043,16 +1043,9 @@ func nextGame(httpClient *http.Client, count int) error {
 	return errors.New("Unknown game type: " + nextGame.Type)
 }
 
-// Check if PGN may contain "e.p." to verify that the chess package is recent
-func testEP() {
-	game := chess.NewGame(chess.UseNotation(chess.AlgebraicNotation{}))
-	game.MoveStr("a4")
-	game.MoveStr("c5")
-	game.MoveStr("a5")
-	game.MoveStr("b5")
-	game.MoveStr("axb6")
-
-	if strings.Contains(game.String(), "e.p.") {
+// Ensure Tilps/chess is new enough.
+func testChessVersion() {
+	if chess.GetLibraryVersion() < 3 {
 		log.Fatal("You need a more recent version of package github.com/Tilps/chess")
 	}
 }
@@ -1086,7 +1079,7 @@ func maybeSetTrainOnly() {
 func main() {
 	fmt.Printf("Lc0 client version %v\n", getExtraParams()["version"])
 
-	testEP()
+	testChessVersion()
 
 	hideLc0argsFlag()
 	flag.Parse()