diff --git a/nginx-sys/build.rs b/nginx-sys/build.rs
index 20a56c3..77542df 100644
--- a/nginx-sys/build.rs
+++ b/nginx-sys/build.rs
@@ -216,7 +216,7 @@ fn pcre_archive_url(version: &String) -> String {
 
 fn openssl_archive_url(version: &String) -> String {
     if version.starts_with("1.1.1") {
-        let version_hyphened = version.replace(".", "_");
+        let version_hyphened = version.replace('.', "_");
         format!("{OPENSSL_DOWNLOAD_URL_PREFIX}/OpenSSL_{version_hyphened}/openssl-{version}.tar.gz")
     } else {
         format!("{OPENSSL_DOWNLOAD_URL_PREFIX}/openssl-{version}/openssl-{version}.tar.gz")