diff --git a/README.md b/README.md
index 7e89712f..508b7b99 100644
--- a/README.md
+++ b/README.md
@@ -15,7 +15,7 @@ libcoap is a C implementation of a lightweight application-protocol
 for devices that are constrained their resources such as computing
 power, RF range, memory, bandwidth, or network packet sizes. This
 protocol, CoAP, is standardized by the IETF as RFC 7252. For further
-information related to CoAP, see <http://coap.space> or
+information related to CoAP, see <https://coap.space> or
 [CoAP Wiki](https://en.wikipedia.org/wiki/Constrained_Application_Protocol).
 
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