diff --git a/CHANGELOG.md b/CHANGELOG.md
index 09eee0389..4b6a1f1bb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,7 +4,7 @@
 
 1.0 is a rewrite of many internals of the gem. Please see the [wiki page on v1.0](https://github.com/shioyama/mobility/wiki/Introduction-to-Mobility-v1.0) for more details on how to upgrade.
 
-## (unreleased)
+## 1.0.0
 
 - Fix setting a locale from Rails config
 	([#468](https://github.com/shioyama/mobility/pull/468)) thanks
diff --git a/README.md b/README.md
index 05b132ec3..fdbe8234e 100644
--- a/README.md
+++ b/README.md
@@ -12,10 +12,8 @@ Mobility
 [docs]: http://www.rubydoc.info/gems/mobility
 [wiki]: https://github.com/shioyama/mobility/wiki
 
-**This is the readme for the [`master`](https://github.com/shioyama/mobility)
-branch, which corresponds to v1.0.0.rc1, a pre-release version of Mobility.
-If you are using an earlier version (0.8.x or earlier), you probably want the
-readme on the [0-8-stable
+**This is the readme for version 1.0 of Mobility. If you are using an earlier
+version (0.8.x or earlier), you probably want the readme on the [0-8-stable
 branch](https://github.com/shioyama/mobility/tree/0-8-stable).**
 
 Mobility is a gem for storing and retrieving translations as attributes on a
@@ -58,7 +56,7 @@ To use the latest pre-version of Mobility 1.0, add this line to your
 application's Gemfile:
 
 ```ruby
-gem 'mobility', '~> 1.0.0.rc1'
+gem 'mobility', '~> 1.0.0'
 ```
 
 For the latest stable version of Mobility, see the readme on the
diff --git a/lib/mobility/version.rb b/lib/mobility/version.rb
index 7ece2827c..6677bcfe1 100644
--- a/lib/mobility/version.rb
+++ b/lib/mobility/version.rb
@@ -9,7 +9,7 @@ module VERSION
     MAJOR = 1
     MINOR = 0
     TINY = 0
-    PRE = "rc1"
+    PRE = nil
 
     STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
   end
diff --git a/mobility.gemspec b/mobility.gemspec
index 41978f38e..f6761eeaa 100644
--- a/mobility.gemspec
+++ b/mobility.gemspec
@@ -35,4 +35,12 @@ Gem::Specification.new do |spec|
 
   spec.cert_chain = ["certs/shioyama.pem"]
   spec.signing_key = File.expand_path("~/.ssh/gem-private_key.pem") if $0 =~ /gem\z/
+
+  spec.post_install_message = %q{
+Warning: Mobility v1.0 includes backwards-incompatible changes (mostly around configuration).
+
+If you are upgrading from an earlier version, please see:
+- https://github.com/shioyama/mobility/releases/tag/v1.0.0
+- https://github.com/shioyama/mobility/wiki/Introduction-to-Mobility-v1.0
+}
 end