diff --git a/README b/README
index ca3401c1..867c1b5d 100644
--- a/README
+++ b/README
@@ -36,7 +36,8 @@ Requirements
  - pkg-config >= 0.22
  - libglib >= 2.32.0
  - libzip >= 0.10
- - libusb-1.0 >= 1.0.9 (optional, used by most drivers)
+ - libserialport >= 0.1 (optional, used by some drivers)
+ - libusb-1.0 >= 1.0.9 (optional, used by some drivers)
  - libftdi >= 0.16 (optional, used by some drivers)
  - libudev >= 151 (optional, used by some drivers)
  - libasound / alsa-lib >= 1.0 (optional, only used by the alsa driver)