diff --git a/.travis.yml b/.travis.yml
index 39907f2..a69fec1 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,20 +1,24 @@
 language: elixir
 matrix:
   include:
-    - otp_release: 20.0
-      elixir: 1.8
+# TODO: temporarily disabled since the newest version of Hackney (used by excoveralls) doesn't seem to work with OTP 20 ("Compiling src/hackney_ssl.erl failed")
+#    - otp_release: 20.0
+#      elixir: 1.8
     - otp_release: 21.0
       elixir: 1.8
     - otp_release: 22.0
       elixir: 1.8
-    - otp_release: 20.0
-      elixir: 1.9
+# TODO: temporarily disabled since the newest version of Hackney (used by excoveralls) doesn't seem to work with OTP 20 ("Compiling src/hackney_ssl.erl failed")
+#    - otp_release: 20.0
+#      elixir: 1.9
     - otp_release: 22.0
       elixir: 1.9
     - otp_release: 21.0
       elixir: 1.10
     - otp_release: 22.0
       elixir: 1.10
+    - otp_release: 23.0
+      elixir: 1.10
 sudo: false
 after_script:
   - MIX_ENV=docs mix deps.get