diff --git a/.travis.yml b/.travis.yml
index afea4e6..de5abf9 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,9 @@
 language: erlang
 otp_release:
+  - 21.0.2
+  - 20.3
+  - 19.3
+  - 18.3
   - 17.4
   - 17.3
   - 17.1
diff --git a/rebar.config b/rebar.config
index deada4c..1d494ca 100644
--- a/rebar.config
+++ b/rebar.config
@@ -9,7 +9,7 @@
 {profiles, [
   {test, [
     {plugins, [
-        {rebar3_eqc, ".*", {git, "https://github.com/kellymclaughlin/rebar3-eqc-plugin.git", {tag, "0.0.8"}}}
+        {rebar3_eqc, ".*", {git, "https://github.com/kellymclaughlin/rebar3-eqc-plugin.git", {tag, "0.1.0"}}}
     ]}
   ]
 }]}.
diff --git a/rebar.lock b/rebar.lock
new file mode 100644
index 0000000..57afcca
--- /dev/null
+++ b/rebar.lock
@@ -0,0 +1 @@
+[].
diff --git a/src/poolboy.erl b/src/poolboy.erl
index db4973b..42c5085 100644
--- a/src/poolboy.erl
+++ b/src/poolboy.erl
@@ -18,6 +18,14 @@
 -type pid_queue() :: queue:queue().
 -endif.
 
+-ifdef(OTP_RELEASE). %% this implies 21 or higher
+-define(EXCEPTION(Class, Reason, Stacktrace), Class:Reason:Stacktrace).
+-define(GET_STACK(Stacktrace), Stacktrace).
+-else.
+-define(EXCEPTION(Class, Reason, _), Class:Reason).
+-define(GET_STACK(_), erlang:get_stacktrace()).
+-endif.
+
 -type pool() ::
     Name :: (atom() | pid()) |
     {Name :: atom(), node()} |
@@ -54,9 +62,9 @@ checkout(Pool, Block, Timeout) ->
     try
         gen_server:call(Pool, {checkout, CRef, Block}, Timeout)
     catch
-        Class:Reason ->
+        ?EXCEPTION(Class, Reason, Stacktrace) ->
             gen_server:cast(Pool, {cancel_waiting, CRef}),
-            erlang:raise(Class, Reason, erlang:get_stacktrace())
+            erlang:raise(Class, Reason, ?GET_STACK(Stacktrace))
     end.
 
 -spec checkin(Pool :: pool(), Worker :: pid()) -> ok.
diff --git a/test/poolboy_eqc.erl b/test/poolboy_eqc.erl
index 59031d4..b49b413 100644
--- a/test/poolboy_eqc.erl
+++ b/test/poolboy_eqc.erl
@@ -1,5 +1,5 @@
 -module(poolboy_eqc).
--compile([export_all]).
+-compile([export_all, nowarn_export_all]).
 
 -ifdef(TEST).
 -ifdef(EQC).
diff --git a/test/poolboy_tests.erl b/test/poolboy_tests.erl
index b0f3b39..552f6e9 100644
--- a/test/poolboy_tests.erl
+++ b/test/poolboy_tests.erl
@@ -516,7 +516,7 @@ reuses_waiting_monitor_on_worker_exit() ->
         receive ok -> ok end
     end),
 
-    Worker = receive {worker, Worker} -> Worker end,
+    Worker = receive {worker, Worker1} -> Worker1 end,
     Ref = monitor(process, Worker),
     exit(Worker, kill),
     receive