diff --git a/rebar.config b/rebar.config
index d6ecbf2..0a2bc86 100644
--- a/rebar.config
+++ b/rebar.config
@@ -39,7 +39,7 @@
 {alias, [{test, [format, lint, hank, xref, dialyzer, eunit, cover]}]}.
 
 {project_plugins,
- [{rebar3_hex, "~> 6.11.0"},
+ [{rebar3_hex, "~> 6.11.4"},
   {rebar3_format, "~> 1.0.0"},
   {rebar3_lint, "~> 0.4.0"},
-  {rebar3_hank, "~> 0.4.0"}]}.
+  {rebar3_hank, "~> 1.1.2"}]}.
diff --git a/src/awsv4.erl b/src/awsv4.erl
index fe4ab54..3a18c8b 100644
--- a/src/awsv4.erl
+++ b/src/awsv4.erl
@@ -76,7 +76,9 @@ headers(#credentials{secret_access_key = SecretAccessKey,
     Hash = sha256,
     Algorithm = "AWS4-HMAC-SHA256",
     SigningKey =
-        lists:foldl(fun(E, A) -> crypto:hmac(Hash, A, E) end, "AWS4" ++ SecretAccessKey, Scope),
+        lists:foldl(fun(E, A) -> crypto:mac(hmac, Hash, A, E) end,
+                    "AWS4" ++ SecretAccessKey,
+                    Scope),
 
     Headers =
         lists:keysort(1,
@@ -116,7 +118,7 @@ headers(#credentials{secret_access_key = SecretAccessKey,
               CredentialScope,
               hexlify(crypto:hash(Hash, CanonicalRequest))]),
 
-    Signature = hexlify(crypto:hmac(Hash, SigningKey, StringToSign)),
+    Signature = hexlify(crypto:mac(hmac, Hash, SigningKey, StringToSign)),
 
     [{"authorization",
       [Algorithm,
diff --git a/src/imds.erl b/src/imds.erl
index 5c4ac9e..a3ed8e8 100644
--- a/src/imds.erl
+++ b/src/imds.erl
@@ -40,7 +40,7 @@ public_hostname() ->
 get_session_token() ->
     case role_name() of
         {ok, RoleName} ->
-            Result = imds_tokens(["iam/security-credentials/", http_uri:encode(RoleName)]),
+            Result = imds_tokens(["iam/security-credentials/", RoleName]),
             awsv4:credentials_from_plist(Result);
         Error ->
             Error
@@ -178,7 +178,7 @@ call_with_retry(_, _, _, _, _) ->
     {error, retries_exceeded}.
 
 imds_url(Suffix) ->
-    lists:flatten(["http://", ?IMDS_HOST, "/", ?IMDS_VERSION, "/meta-data/", Suffix]).
+    uri_string:normalize(["http://", ?IMDS_HOST, "/", ?IMDS_VERSION, "/meta-data/", Suffix]).
 
 imds_text(Suffix) ->
     imds_text_response(imds_url(Suffix)).