diff --git a/implementations/rust/preserves/src/value/text/writer.rs b/implementations/rust/preserves/src/value/text/writer.rs
index 5d37755..3d2cf9b 100644
--- a/implementations/rust/preserves/src/value/text/writer.rs
+++ b/implementations/rust/preserves/src/value/text/writer.rs
@@ -311,7 +311,7 @@ impl<W: io::Write> Writer for TextWriter<W> {
         write!(
             self.w,
             "#[{}]",
-            base64::encode_config(v, base64::STANDARD_NO_PAD)
+            base64::encode_config(v, base64::URL_SAFE_NO_PAD)
         )
     }