diff --git a/Cargo.toml b/Cargo.toml
index ae822ee..60e7eea 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -76,7 +76,7 @@ __rustls = ["hyper-rustls", "tokio-rustls", "rustls", "__tls", "rustls-pemfile"]
 __internal_proxy_sys_no_cache = []
 
 [dependencies]
-base64 = "0.13"
+base64 = "0.20"
 http = "0.2"
 url = "2.2"
 bytes = "1.0"
diff --git a/src/async_impl/request.rs b/src/async_impl/request.rs
index 3a38aa4..5148219 100644
--- a/src/async_impl/request.rs
+++ b/src/async_impl/request.rs
@@ -253,7 +253,7 @@ impl RequestBuilder {
     {
         let mut header_value = b"Basic ".to_vec();
         {
-            let mut encoder = Base64Encoder::new(&mut header_value, base64::STANDARD);
+            let mut encoder = Base64Encoder::from(&mut header_value, &base64::engine::DEFAULT_ENGINE);
             // The unwraps here are fine because Vec::write* is infallible.
             write!(encoder, "{}:", username).unwrap();
             if let Some(password) = password {
diff --git a/src/wasm/request.rs b/src/wasm/request.rs
index 432f5bb..d1c1b4a 100644
--- a/src/wasm/request.rs
+++ b/src/wasm/request.rs
@@ -216,7 +216,7 @@ impl RequestBuilder {
     {
         let mut header_value = b"Basic ".to_vec();
         {
-            let mut encoder = Base64Encoder::new(&mut header_value, base64::STANDARD);
+            let mut encoder = Base64Encoder::from(&mut header_value, &base64::engine::DEFAULT_ENGINE);
             // The unwraps here are fine because Vec::write* is infallible.
             write!(encoder, "{}:", username).unwrap();
             if let Some(password) = password {