diff --git a/.travis.yml b/.travis.yml
index e22719e..d061bd5 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,6 @@
 language: rust
 rust:
-  - 1.31.0
+  - 1.35.0
   - stable
   - beta
   - nightly
diff --git a/Cargo.toml b/Cargo.toml
index 96ebe67..11fad5f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -18,7 +18,7 @@ locale = "0.2"
 num-traits = "0.2"
 pad = "0.1"
 libc = "0.2"
-iso8601 = "0.3.0"
+iso8601 = "0.4"
 
 
 [target.'cfg(windows)'.dependencies]
diff --git a/README.md b/README.md
index 622613c..c81d27a 100644
--- a/README.md
+++ b/README.md
@@ -14,4 +14,4 @@ This crate works with [Cargo](https://crates.io). Add the following to your `Car
 datetime = "0.5"
 ```
 
-The earliest version of Rust that this crate is tested against is [Rust v1.31.0](https://blog.rust-lang.org/2018/12/06/Rust-1.31-and-rust-2018.html).
+The earliest version of Rust that this crate is tested against is [Rust v1.35.0](https://blog.rust-lang.org/2019/05/23/Rust-1.35.0.html).