diff --git a/aquatic_udp/src/lib/common/mod.rs b/aquatic_udp/src/lib/common/mod.rs
index 41c52e8..b0674ff 100644
--- a/aquatic_udp/src/lib/common/mod.rs
+++ b/aquatic_udp/src/lib/common/mod.rs
@@ -269,18 +269,6 @@ impl Default for State {
         }
     }
 }
-pub fn ip_version_from_ip(ip: IpAddr) -> IpVersion {
-    match ip {
-        IpAddr::V4(_) => IpVersion::IPv4,
-        IpAddr::V6(ip) => {
-            if let [0, 0, 0, 0, 0, 0xffff, ..] = ip.segments() {
-                IpVersion::IPv4
-            } else {
-                IpVersion::IPv6
-            }
-        }
-    }
-}
 
 #[cfg(test)]
 mod tests {
diff --git a/aquatic_udp_protocol/src/common.rs b/aquatic_udp_protocol/src/common.rs
index 6070e29..77192c6 100644
--- a/aquatic_udp_protocol/src/common.rs
+++ b/aquatic_udp_protocol/src/common.rs
@@ -1,11 +1,5 @@
 use std::net::{Ipv4Addr, Ipv6Addr};
 
-#[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)]
-pub enum IpVersion {
-    IPv4,
-    IPv6,
-}
-
 #[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)]
 pub struct AnnounceInterval(pub i32);
 
@@ -48,17 +42,6 @@ pub struct ResponsePeerIpv6 {
     pub port: Port,
 }
 
-#[cfg(test)]
-impl quickcheck::Arbitrary for IpVersion {
-    fn arbitrary(g: &mut quickcheck::Gen) -> Self {
-        if bool::arbitrary(g) {
-            IpVersion::IPv4
-        } else {
-            IpVersion::IPv6
-        }
-    }
-}
-
 #[cfg(test)]
 impl quickcheck::Arbitrary for InfoHash {
     fn arbitrary(g: &mut quickcheck::Gen) -> Self {