diff --git a/.travis.yml b/.travis.yml
index a62423fb7a..1020d2b8e3 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,9 +2,9 @@
 
 language: rust
 rust:
-    - stable
-    # The version of rust in the latest Ubuntu LTS, currently Bionic.
-    - 1.25.0
+    # The oldest version we currently support. See
+    # CONTRIBUTING.md#rustc-version-support for details.
+    - 1.29.0
     - beta
     - nightly
 matrix:
diff --git a/cranelift/CONTRIBUTING.md b/cranelift/CONTRIBUTING.md
index a5f5aad334..89aff16fec 100644
--- a/cranelift/CONTRIBUTING.md
+++ b/cranelift/CONTRIBUTING.md
@@ -75,17 +75,14 @@ which may be convenient when there are multiple versions installed.
 
 ### Rustc version support
 
-Our current policy is to support the version of Rustc that ships with the
-latest Ubuntu LTS release, as well as the current stable version. This means
-we don't use some of the very latest released Rust features.
+Cranelift supports stable Rust, and follows the
+[Rust Update Policy for Firefox].
 
 Some of the developer scripts depend on nightly Rust, for example to run
 clippy and other tools, however we avoid depending on these for the main
 build.
 
-That said, if there are any new Rust features that would be particularly
-valuable to use, please bring them up, as we may be able to find ways to
-accommodate them.
+[Rust Update Policy for Firefox]: https://wiki.mozilla.org/Rust_Update_Policy_for_Firefox#Schedule
 
 ### Python
 
diff --git a/cranelift/README.md b/cranelift/README.md
index 8e65e72ebf..cb567cd5a5 100644
--- a/cranelift/README.md
+++ b/cranelift/README.md
@@ -9,7 +9,7 @@ into executable machine code.
 [![Documentation Status](https://readthedocs.org/projects/cranelift/badge/?version=latest)](https://cranelift.readthedocs.io/en/latest/?badge=latest)
 [![Build Status](https://travis-ci.org/CraneStation/cranelift.svg?branch=master)](https://travis-ci.org/CraneStation/cranelift)
 [![Gitter chat](https://badges.gitter.im/CraneStation/CraneStation.svg)](https://gitter.im/CraneStation/Lobby)
-![Minimum rustc 1.25](https://img.shields.io/badge/rustc-1.25+-red.svg)
+![Minimum rustc 1.29](https://img.shields.io/badge/rustc-1.29+-red.svg)
 
 For more information, see [the
 documentation](https://cranelift.readthedocs.io/en/latest/?badge=latest).
@@ -47,11 +47,8 @@ needed before it would be ready for a production use case.
 
 Cranelift's APIs are not yet stable.
 
-Cranelift currently supports Rust 1.25.0 and later. We intend to always
-support the latest *stable* Rust. And, we currently support the version
-of Rust in the latest Ubuntu LTS, although whether we will always do so
-is not yet determined. Cranelift requires Python 2.7 or Python 3 to
-build.
+Cranelift currently requires Rust 1.29 or later, and Python 2.7 or 3
+to build.
 
 Planned uses
 ------------