diff --git a/base/testnet.go b/base/testnet.go
index f33708f..72408b7 100644
--- a/base/testnet.go
+++ b/base/testnet.go
@@ -1,3 +1,4 @@
+//go:build testnet
 // +build testnet
 
 /*
@@ -36,7 +37,7 @@ var (
 	MATIC    uint64 = 202
 	ARBITRUM uint64 = 205
 	XDAI     uint64 = 206
-	OPTIMISM uint64 = 207
+	OPTIMISM uint64 = 210
 	FANTOM   uint64 = 208
 	AVA      uint64 = 209
 	METIS    uint64 = 300