diff --git a/zerotier-core-crypto/Cargo.toml b/zerotier-core-crypto/Cargo.toml
index 9d7af8642..3e333767d 100644
--- a/zerotier-core-crypto/Cargo.toml
+++ b/zerotier-core-crypto/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "zerotier-core-crypto"
 version = "0.1.0"
-edition = "2018"
+edition = "2021"
 license = "MPL-2.0"
 authors = ["ZeroTier, Inc. <contact@zerotier.com>", "Adam Ierymenko <adam.ierymenko@zerotier.com>"]
 
diff --git a/zerotier-core-crypto/src/array_concat.rs b/zerotier-core-crypto/src/array_concat.rs
index de1baa2de..187b578d9 100644
--- a/zerotier-core-crypto/src/array_concat.rs
+++ b/zerotier-core-crypto/src/array_concat.rs
@@ -52,3 +52,21 @@ pub fn concat_4_slices<const S0: usize, const S1: usize, const S2: usize, const
 pub fn concat_4_arrays<const S0: usize, const S1: usize, const S2: usize, const S3: usize, const S: usize>(s0: &[u8; S0], s1: &[u8; S1], s2: &[u8; S2], s3: &[u8; S3]) -> [u8; S] {
     concat_4_slices::<S0, S1, S2, S3, S>(s0, s1, s2, s3)
 }
+
+
+#[inline(always)]
+pub fn concat_5_slices<const S0: usize, const S1: usize, const S2: usize, const S3: usize, const S4: usize, const S: usize>(s0: &[u8], s1: &[u8], s2: &[u8], s3: &[u8], s4: &[u8]) -> [u8; S] {
+    debug_assert_eq!(S0 + S1 + S2 + S3 + S4, S);
+    let mut tmp: [u8; S] = unsafe { MaybeUninit::uninit().assume_init() };
+    tmp[..S0].copy_from_slice(s0);
+    tmp[S0..S1].copy_from_slice(s1);
+    tmp[(S0 + S1)..(S0 + S1 + S2)].copy_from_slice(s2);
+    tmp[(S0 + S1 + S2)..(S0 + S1 + S2 + S3)].copy_from_slice(s3);
+    tmp[(S0 + S1 + S2 + S3)..].copy_from_slice(s4);
+    tmp
+}
+
+#[inline(always)]
+pub fn concat_5_arrays<const S0: usize, const S1: usize, const S2: usize, const S3: usize, const S4: usize, const S: usize>(s0: &[u8; S0], s1: &[u8; S1], s2: &[u8; S2], s3: &[u8; S3], s4: &[u8; S4]) -> [u8; S] {
+    concat_5_slices::<S0, S1, S2, S3, S4, S>(s0, s1, s2, s3, s4)
+}
diff --git a/zerotier-network-hypervisor/Cargo.toml b/zerotier-network-hypervisor/Cargo.toml
index 09d938a61..ca12737a4 100644
--- a/zerotier-network-hypervisor/Cargo.toml
+++ b/zerotier-network-hypervisor/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "zerotier-network-hypervisor"
 version = "2.0.0"
-edition = "2018"
+edition = "2021"
 license = "MPL-2.0"
 authors = ["ZeroTier, Inc. <contact@zerotier.com>", "Adam Ierymenko <adam.ierymenko@zerotier.com>"]
 
diff --git a/zerotier-system-service/Cargo.toml b/zerotier-system-service/Cargo.toml
index f8c281099..844c8da39 100644
--- a/zerotier-system-service/Cargo.toml
+++ b/zerotier-system-service/Cargo.toml
@@ -2,7 +2,7 @@
 name = "zerotier-system-service"
 version = "0.1.0"
 authors = ["ZeroTier, Inc. <contact@zerotier.com>", "Adam Ierymenko <adam.ierymenko@zerotier.com>"]
-edition = "2018"
+edition = "2021"
 license = "MPL-2.0"
 
 [profile.release]