diff --git a/.circleci/config.yml b/.circleci/config.yml
index 6a197d6..70eb080 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -20,7 +20,7 @@ workflows:
               # get a nightly or stable toolchain via rustup instead of a mutable docker tag
               toolchain_override: [
                 '__msrv__', # won't add any other toolchains, just uses what's in the docker image
-                '1.63.0', # minimum needed to build dev-dependencies
+                '1.65.0', # minimum needed to build dev-dependencies
                 'stable',
                 'beta',
                 'nightly'
diff --git a/Cargo.toml b/Cargo.toml
index d7f1d76..4bb27e1 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,7 +10,7 @@ keywords = ["base64", "utf8", "encode", "decode", "no_std"]
 categories = ["encoding"]
 license = "MIT OR Apache-2.0"
 edition = "2018"
-# dev-dependencies require 1.63, but the main code doesn't
+# dev-dependencies require 1.65, but the main code doesn't
 # This option was added in 1.56, keep it for when we bump MSRV.
 rust-version = "1.48.0"
 
diff --git a/RELEASE-NOTES.md b/RELEASE-NOTES.md
index dcd7d30..d6d94c5 100644
--- a/RELEASE-NOTES.md
+++ b/RELEASE-NOTES.md
@@ -1,3 +1,7 @@
+# 0.21.5
+
+- Add `Debug` and `Clone` impls for the general purpose Engine
+
 # 0.21.4
 
 - Make `encoded_len` `const`, allowing the creation of arrays sized to encode compile-time-known data lengths
diff --git a/benches/benchmarks.rs b/benches/benchmarks.rs
index 61d542f..802c8cc 100644
--- a/benches/benchmarks.rs
+++ b/benches/benchmarks.rs
@@ -39,8 +39,7 @@ fn do_decode_bench_slice(b: &mut Bencher, &size: &usize) {
     fill(&mut v);
     let encoded = STANDARD.encode(&v);
 
-    let mut buf = Vec::new();
-    buf.resize(size, 0);
+    let mut buf = vec![0; size];
     b.iter(|| {
         STANDARD.decode_slice(&encoded, &mut buf).unwrap();
         black_box(&buf);
@@ -52,8 +51,7 @@ fn do_decode_bench_stream(b: &mut Bencher, &size: &usize) {
     fill(&mut v);
     let encoded = STANDARD.encode(&v);
 
-    let mut buf = Vec::new();
-    buf.resize(size, 0);
+    let mut buf = vec![0; size];
     buf.truncate(0);
 
     b.iter(|| {
@@ -96,9 +94,8 @@ fn do_encode_bench_reuse_buf(b: &mut Bencher, &size: &usize) {
 fn do_encode_bench_slice(b: &mut Bencher, &size: &usize) {
     let mut v: Vec<u8> = Vec::with_capacity(size);
     fill(&mut v);
-    let mut buf = Vec::new();
     // conservative estimate of encoded size
-    buf.resize(v.len() * 2, 0);
+    let mut buf = vec![0; v.len() * 2];
     b.iter(|| STANDARD.encode_slice(&v, &mut buf).unwrap());
 }
 
diff --git a/src/engine/general_purpose/mod.rs b/src/engine/general_purpose/mod.rs
index 01d2204..e0227f3 100644
--- a/src/engine/general_purpose/mod.rs
+++ b/src/engine/general_purpose/mod.rs
@@ -19,6 +19,8 @@ pub(crate) const INVALID_VALUE: u8 = 255;
 /// - It uses no vector CPU instructions, so it will work on any system.
 /// - It is reasonably fast (~2-3GiB/s).
 /// - It is not constant-time, though, so it is vulnerable to timing side-channel attacks. For loading cryptographic keys, etc, it is suggested to use the forthcoming constant-time implementation.
+
+#[derive(Debug, Clone)]
 pub struct GeneralPurpose {
     encode_table: [u8; 64],
     decode_table: [u8; 256],
diff --git a/src/read/decoder_tests.rs b/src/read/decoder_tests.rs
index 625a07d..099dd63 100644
--- a/src/read/decoder_tests.rs
+++ b/src/read/decoder_tests.rs
@@ -76,7 +76,7 @@ fn trailing_junk() {
                         saw_error = true;
                         break;
                     }
-                    Ok(read) if read == 0 => break,
+                    Ok(0) => break,
                     Ok(_) => (),
                 }
             }