diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,1 +1,44 @@
-TODO
+## [*Unreleased*](https://github.com/pbrisbin/load-env/compare/v0.2.0.2...master)
+
+None
+
+## [v0.2.0.2](https://github.com/pbrisbin/load-env/compare/v0.2.0.1...v0.2.0.2)
+
+- Allow lower-case characters in variable names [@denibertovic](https://github.com/pbrisbin/load-env/pull/4)
+
+## [v0.2.0.1](https://github.com/pbrisbin/load-env/compare/v0.2.0.0...v0.2.0.1)
+
+- Packaging and documentation updates
+
+## [v0.2.0.0](https://github.com/pbrisbin/load-env/compare/v0.1.2...v0.2.0.0)
+
+- Traverse up parent directories to find the `.env` file
+
+## [v0.1.2](https://github.com/pbrisbin/load-env/compare/v0.1.1...v0.1.2)
+
+- Packaging updates
+
+## [v0.1.1](https://github.com/pbrisbin/load-env/compare/v0.1.0...v0.1.1)
+
+- Parse variables names more strictly
+
+## [v0.1.0](https://github.com/pbrisbin/load-env/compare/v0.0.4...v0.1.0)
+
+- Don't fail on an empty file
+- Ignore any invalid lines, not specifically things that look like comments
+
+## [v0.0.4](https://github.com/pbrisbin/load-env/compare/v0.0.3...v0.0.4)
+
+- Don't throw an exception if the `.env` file is missing
+
+## [v0.0.3](https://github.com/pbrisbin/load-env/compare/v0.0.2...v0.0.3)
+
+- Variable names can contain underscores
+
+## [v0.0.2](https://github.com/pbrisbin/load-env/compare/v0.0.1...v0.0.2)
+
+- Drop support for GHC < 7.8
+
+## [v0.0.1](https://github.com/pbrisbin/load-env/tree/v0.0.1)
+
+Initial release.
diff --git a/load-env.cabal b/load-env.cabal
--- a/load-env.cabal
+++ b/load-env.cabal
@@ -2,10 +2,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 2e4f7d0d54d77f91f6586cbaae5aef26c673de9f74d2d3b0447d42773e3630c0
+-- hash: c39eb0ad2f6482017271ab93ef8f962a61068806291ebaa457c3fa6f3dd34055
 
 name:           load-env
-version:        0.2.0.1
+version:        0.2.0.2
 synopsis:       Load environment variables from a file.
 description:    Parse a .env file and load any declared variables into the current process's environment. This allows for a .env file to specify development-friendly defaults for configuration values normally set in the deployment environment.
 category:       Configuration
diff --git a/src/LoadEnv/Parse.hs b/src/LoadEnv/Parse.hs
--- a/src/LoadEnv/Parse.hs
+++ b/src/LoadEnv/Parse.hs
@@ -38,16 +38,22 @@
     pure (i, v)
 
 -- Environment variable names used by the utilities in the Shell and Utilities
--- volume of IEEE Std 1003.1-2001 consist solely of uppercase letters, digits,
--- and the '_' (underscore) from the characters defined in Portable Character
--- Set and do not begin with a digit.
+-- volume of POSIX.1-2017 consist solely of uppercase letters, digits,
+-- and the <underscore> ( '_' ) from the characters defined in Portable
+-- Character Set and do not begin with a digit. Other characters may be
+-- permitted by an implementation; applications shall tolerate the presence
+-- of such names. Uppercase and lowercase letters shall retain their unique
+-- identities and shall not be folded together. The name space of environment
+-- variable names containing lowercase letters is reserved for applications.
+-- Applications can define any environment variables with names from this name
+-- space without modifying the behavior of the standard utilities.
 --
--- <http://pubs.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap08.html>
+-- <http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html>
 --
 identifier :: Parser String
 identifier = do
-    x <- upper <|> underscore
-    ys <- many $ upper <|> digit <|> underscore
+    x <- upper <|> lower <|> underscore
+    ys <- many $ upper <|>  lower <|> digit <|> underscore
 
     pure (x:ys)
 
diff --git a/test/LoadEnv/ParseSpec.hs b/test/LoadEnv/ParseSpec.hs
--- a/test/LoadEnv/ParseSpec.hs
+++ b/test/LoadEnv/ParseSpec.hs
@@ -97,13 +97,15 @@
                 `shouldBe` Right ("S3_KEY", "abc123")
             parse parseVariable "" "_S3_KEY=abc123\n"
                 `shouldBe` Right ("_S3_KEY", "abc123")
+            parse parseVariable "" "S3_key=abc123\n"
+                `shouldBe` Right ("S3_key", "abc123")
+            parse parseVariable "" "s3_key=abc123\n"
+                `shouldBe` Right ("s3_key", "abc123")
 
             parse parseVariable "" "S3~KEY=abc123\n"
                 `shouldContainError` "unexpected \"~\""
             parse parseVariable "" "S3-KEY=abc123\n"
                 `shouldContainError` "unexpected \"-\""
-            parse parseVariable "" "S3_key=abc123\n"
-                `shouldContainError` "unexpected \"k\""
             parse parseVariable "" "3_KEY=abc123\n"
                 `shouldContainError` "unexpected \"3\""