diff --git a/CHANGES.md b/CHANGES.md
index 18af675..7cb6269 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,10 @@
+2.0.0 (2014-12-24):
+* Switch the top-level `Base64` module to `B64` to avoid
+  clashing with various other similarly named modules in
+  `extlib` and some other libraries.  This is obviously
+  backwards compatibility breaking with all current users
+  of this library. (#3).
+
 1.1.0 (2014-12-16):
 * Allow specifying a different alphabet during encoding or
   decoding, and supply a URI-safe alphabet along with the
diff --git a/_oasis b/_oasis
index 27b835b..14ea427 100644
--- a/_oasis
+++ b/_oasis
@@ -1,6 +1,6 @@
 OASISFormat: 0.4
 Name:        base64
-Version:     1.1.0
+Version:     2.0.0
 Synopsis:    Base64 encoding library
 Authors:     Thomas Gazagnaire, Anil Madhavapeddy, Peter Zotov
 License:     ISC
@@ -9,7 +9,7 @@ BuildTools:  ocamlbuild
 
 Library base64
   Path: lib
-  Modules: Base64
+  Modules: B64
   BuildDepends: bytes
 
 AlphaFeatures: ocamlbuild_more_args
diff --git a/api.odocl b/api.odocl
index bfe9565..b06a581 100644
--- a/api.odocl
+++ b/api.odocl
@@ -1,4 +1,4 @@
 # OASIS_START
-# DO NOT EDIT (digest: a2aac417857692f1f06cfab146a3595e)
-lib/Base64
+# DO NOT EDIT (digest: 6b153de2d42f2ecbe317d5cc18b73faa)
+lib/B64
 # OASIS_STOP
diff --git a/lib/META b/lib/META
index ec2eea0..2a5716e 100644
--- a/lib/META
+++ b/lib/META
@@ -1,6 +1,6 @@
 # OASIS_START
-# DO NOT EDIT (digest: d900c0db6c33f5db7083c274080c31f6)
-version = "1.1.0"
+# DO NOT EDIT (digest: 7c89ecbf231e96fc39574897c8f1b40a)
+version = "2.0.0"
 description = "Base64 encoding library"
 requires = "bytes"
 archive(byte) = "base64.cma"
diff --git a/lib/base64.ml b/lib/b64.ml
similarity index 100%
rename from lib/base64.ml
rename to lib/b64.ml
diff --git a/lib/base64.mli b/lib/b64.mli
similarity index 100%
rename from lib/base64.mli
rename to lib/b64.mli
diff --git a/lib/base64.mldylib b/lib/base64.mldylib
index a8a966e..460c418 100644
--- a/lib/base64.mldylib
+++ b/lib/base64.mldylib
@@ -1,4 +1,4 @@
 # OASIS_START
-# DO NOT EDIT (digest: 1eb445fa6bd078346bf63ecac35fa77c)
-Base64
+# DO NOT EDIT (digest: d5b36098ec1795f41db1bb6de80e04b6)
+B64
 # OASIS_STOP
diff --git a/lib/base64.mllib b/lib/base64.mllib
index a8a966e..460c418 100644
--- a/lib/base64.mllib
+++ b/lib/base64.mllib
@@ -1,4 +1,4 @@
 # OASIS_START
-# DO NOT EDIT (digest: 1eb445fa6bd078346bf63ecac35fa77c)
-Base64
+# DO NOT EDIT (digest: d5b36098ec1795f41db1bb6de80e04b6)
+B64
 # OASIS_STOP
diff --git a/opam b/opam
index d308a3a..c1d2206 100644
--- a/opam
+++ b/opam
@@ -1,6 +1,6 @@
 opam-version: "1.2"
 name: "base64"
-version: "1.1.0"
+version: "2.0.0"
 maintainer: "mirageos-devel@lists.xenproject.org"
 authors: [ "Thomas Gazagnaire"
            "Anil Madhavapeddy"
diff --git a/setup.ml b/setup.ml
index f9a818b..8577efa 100644
--- a/setup.ml
+++ b/setup.ml
@@ -1,7 +1,7 @@
 (* setup.ml generated for the first time by OASIS v0.4.4 *)
 
 (* OASIS_START *)
-(* DO NOT EDIT (digest: 2162a5fdbec03f11d58c8d430b433930) *)
+(* DO NOT EDIT (digest: 711cffe6e30773badc9c0c845543933e) *)
 (*
    Regenerated by OASIS v0.4.5
    Visit http://oasis.forge.ocamlcore.org for more information and
@@ -6695,7 +6695,7 @@ let setup_t =
           alpha_features = ["ocamlbuild_more_args"];
           beta_features = [];
           name = "base64";
-          version = "1.1.0";
+          version = "2.0.0";
           license =
             OASISLicense.DEP5License
               (OASISLicense.DEP5Unit
@@ -6771,7 +6771,7 @@ let setup_t =
                       bs_nativeopt = [(OASISExpr.EBool true, [])]
                    },
                    {
-                      lib_modules = ["Base64"];
+                      lib_modules = ["B64"];
                       lib_pack = false;
                       lib_internal_modules = [];
                       lib_findlib_parent = None;
@@ -6815,7 +6815,7 @@ let setup_t =
        };
      oasis_fn = Some "_oasis";
      oasis_version = "0.4.5";
-     oasis_digest = Some "%\155e���\015�,�\024��2��";
+     oasis_digest = Some "!Z\b\022\148X���_1X\012�*\014";
      oasis_exec = None;
      oasis_setup_args = [];
      setup_update = false