diff --git a/src/csharp/ext/grpc_csharp_ext.c b/src/csharp/ext/grpc_csharp_ext.c
index 0d2a74adb6cf3802b7554b5d098d9b26287e7048..0eb236590ce6dbbde3939b4119725ce1740f1471 100644
--- a/src/csharp/ext/grpc_csharp_ext.c
+++ b/src/csharp/ext/grpc_csharp_ext.c
@@ -850,7 +850,7 @@ GPR_EXPORT void GPR_CALLTYPE grpcsharp_redirect_log(grpcsharp_log_func func) {
 typedef void(GPR_CALLTYPE *test_callback_funcptr)(gpr_int32 success);
 
 /* Version info */
-GPR_EXPORT char *GPR_CALLTYPE grpcsharp_version_string() {
+GPR_EXPORT const char *GPR_CALLTYPE grpcsharp_version_string() {
   return grpc_version_string();
 }