diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e631d59..725615a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,7 +12,7 @@ jobs:
       matrix:
         rust:
           - stable
-          - 1.52
+          - 1.56
         include:
           - rust: stable
             extra_components: rustfmt
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f321fed..4a30d62 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@
 *   BREAKING: `retina::client::rtp::Packet` is now
     `retina::rtp::ReceivedPacket`, and field access has been removed in favor
     of accessors.
+*   minimum Rust version is now 1.56.
 
 ## `v0.3.9` (2022-04-12)
 
diff --git a/Cargo.toml b/Cargo.toml
index b9659be..22dc0a6 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -3,12 +3,13 @@ name = "retina"
 version = "0.4.0-alpha.0"
 authors = ["Scott Lamb <slamb@slamb.org>"]
 license = "MIT/Apache-2.0"
-edition = "2018"
+edition = "2021"
 keywords = ["rtsp", "multimedia", "video", "streaming", "ip-camera"]
 categories = ["network-programming", "multimedia"]
 description = "high-level RTSP multimedia streaming library"
 repository = "https://github.com/scottlamb/retina"
 include = ["src/**/*", "benches", "Cargo.toml"]
+rust-version = "1.56"
 
 [dependencies]
 base64 = "0.13.0"
diff --git a/src/codec/h264.rs b/src/codec/h264.rs
index a7f1070..1cca4e3 100644
--- a/src/codec/h264.rs
+++ b/src/codec/h264.rs
@@ -881,7 +881,8 @@ impl Packetizer {
                     data.advance(1);
                     let fu_indicator = (hdr.nal_ref_idc() << 5) | 28;
                     let fu_header = 0b1000_0000 | hdr.nal_unit_type().id(); // START bit set.
-                    let payload = IntoIterator::into_iter([fu_indicator, fu_header])
+                    let payload = [fu_indicator, fu_header]
+                        .into_iter()
                         .chain(data[..max_payload_size - 2].iter().copied());
                     // TODO: ctx and channel_id are placeholders.
                     let pkt = ReceivedPacketBuilder {
diff --git a/src/rtp.rs b/src/rtp.rs
index e998bc8..c909688 100644
--- a/src/rtp.rs
+++ b/src/rtp.rs
@@ -199,10 +199,11 @@ impl RawPacketBuilder {
         if self.payload_type >= 0x80 {
             return Err("payload type too large");
         }
-        let data: Bytes = IntoIterator::into_iter([
+        let data: Bytes = [
             2 << 6, // version=2, no padding, no extensions, no CSRCs.
             if self.mark { 0b1000_0000 } else { 0 } | self.payload_type,
-        ])
+        ]
+        .into_iter()
         .chain(self.sequence_number.to_be_bytes())
         .chain(self.timestamp.to_be_bytes())
         .chain(self.ssrc.to_be_bytes())