diff --git a/rebar.config.script b/rebar.config.script
new file mode 100644
index 0000000..314f3b5
--- /dev/null
+++ b/rebar.config.script
@@ -0,0 +1,9 @@
+case os:getenv("TARGET_ERLANG_VERSION") of
+    false -> CONFIG;
+    [] -> CONFIG;
+    TargetErlangVersionString ->
+        GpbOpts = proplists:get_value(gpb_opts, CONFIG),
+        TargetErlangVersion = {target_erlang_version, list_to_integer(TargetErlangVersionString)},
+        NewGpbOpts = lists:keystore(target_erlang_version, 1, GpbOpts, TargetErlangVersion),
+        lists:keystore(gpb_opts, 1, CONFIG, {gpb_opts, NewGpbOpts})
+end.
diff --git a/src/hex_api_release.erl b/src/hex_api_release.erl
index 2f2f906..0963748 100644
--- a/src/hex_api_release.erl
+++ b/src/hex_api_release.erl
@@ -106,7 +106,7 @@ publish(Config, Tarball) -> publish(Config, Tarball, []).
 %%      }}}
 %% '''
 %% @end
--spec publish(hexcore:config(), binary(), publish_params()) -> hex_api:response().
+-spec publish(hex_core:config(), binary(), publish_params()) -> hex_api:response().
 publish(Config, Tarball, Params) when is_map(Config) andalso is_binary(Tarball) andalso is_list(Params)->
     QueryString = hex_api:encode_query_string([{replace, proplists:get_value(replace, Params, false)}]),
     Path = hex_api:join_path_segments(hex_api:build_repository_path(Config, ["publish"])),
diff --git a/src/hex_http.erl b/src/hex_http.erl
index 04994dc..bed9e9d 100644
--- a/src/hex_http.erl
+++ b/src/hex_http.erl
@@ -7,7 +7,9 @@
 
 -type method() :: get | post | put | patch | delete.
 -type status() :: non_neg_integer().
+-export_type([status/0]).
 -type headers() :: #{binary() => binary()}.
+-export_type([headers/0]).
 -type body() :: {ContentType :: binary(), Body :: binary()} | undefined.
 -type adapter_config() :: map().
 
diff --git a/src/hex_registry.erl b/src/hex_registry.erl
index 4f82e69..b9e8974 100644
--- a/src/hex_registry.erl
+++ b/src/hex_registry.erl
@@ -14,8 +14,8 @@
 ]).
 -include_lib("public_key/include/public_key.hrl").
 
--type private_key() :: public_key:rsa_private_key() | binary().
--type public_key() :: public_key:rsa_public_key() | binary().
+-type private_key() :: #'RSAPrivateKey'{} | binary().
+-type public_key() :: #'RSAPublicKey'{} | binary().
 
 %%====================================================================
 %% API functions