diff --git a/.travis.yml b/.travis.yml
index 6f98dd7..e58355c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,7 +5,7 @@
 language: rust
 cache: cargo
 rust:
-  - nightly
+  - nightly-2019-01-09
 
 env:
   global:
diff --git a/appveyor.yml b/appveyor.yml
index 0348f0d..87a08fd 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -12,11 +12,11 @@
   matrix:
     # Rust - Nightly
     - TARGET: i686-pc-windows-gnu
-      RUST_VERSION: nightly
+      RUST_VERSION: nightly-2019-01-09
       BITS: 32
       MSYS2: 1
     - TARGET: x86_64-pc-windows-msvc
-      RUST_VERSION: nightly
+      RUST_VERSION: nightly-2019-01-09
       BITS: 64
 
 install:
diff --git a/src/client.rs b/src/client.rs
index a4032ad..bffcf92 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -33,7 +33,7 @@
 //!     url::Url::parse("https://static.rust-lang.org/").unwrap(),
 //!     HttpClient::new(),
 //! )
-//! .user_agent_prefix("rustup/1.4.0")
+//! .user_agent("rustup/1.4.0")
 //! .build();
 //!
 //! let mut client = await!(Client::with_root_pinned(
diff --git a/src/repository.rs b/src/repository.rs
index 5d1babc..dfa68ba 100644
--- a/src/repository.rs
+++ b/src/repository.rs
@@ -263,7 +263,7 @@
     url: Url,
     client: Client<C>,
     interchange: PhantomData<D>,
-    user_agent_prefix: Option<String>,
+    user_agent: Option<String>,
     metadata_prefix: Option<Vec<String>>,
     min_bytes_per_second: u32,
 }
@@ -279,7 +279,7 @@
             url: url,
             client: client,
             interchange: PhantomData,
-            user_agent_prefix: None,
+            user_agent: None,
             metadata_prefix: None,
             min_bytes_per_second: 4096,
         }
@@ -290,8 +290,8 @@
     /// Callers *should* include a custom User-Agent prefix to help maintainers of TUF repositories
     /// keep track of which client versions exist in the field.
     ///
-    pub fn user_agent_prefix<T: Into<String>>(mut self, user_agent_prefix: T) -> Self {
-        self.user_agent_prefix = Some(user_agent_prefix.into());
+    pub fn user_agent<T: Into<String>>(mut self, user_agent: T) -> Self {
+        self.user_agent = Some(user_agent.into());
         self
     }
 
@@ -313,9 +313,9 @@
 
     /// Build a `HttpRepository`.
     pub fn build(self) -> HttpRepository<C, D> {
-        let user_agent = match self.user_agent_prefix {
-            Some(ua) => format!("{} (rust-tuf/{})", ua, env!("CARGO_PKG_VERSION")),
-            None => format!("rust-tuf/{}", env!("CARGO_PKG_VERSION")),
+        let user_agent = match self.user_agent {
+            Some(user_agent) => user_agent,
+            None => "rust-tuf".into(),
         };
 
         HttpRepository {