diff --git a/bin/tests/system/doth/tests.sh b/bin/tests/system/doth/tests.sh
index e9bcb89405..5e5c9b0f0e 100644
--- a/bin/tests/system/doth/tests.sh
+++ b/bin/tests/system/doth/tests.sh
@@ -551,7 +551,7 @@ status=$((status + ret))
 
 # check whether we can use curl for sending test queries.
 if [ -x "${CURL}" ] ; then
-	CURL_HTTP2="$(${CURL} --version | grep '^Features:.* HTTP2\( \|$\)')"
+	CURL_HTTP2="$(${CURL} --version | grep -E '^Features:.* HTTP2( |$)')"
 
 	if [ -n "$CURL_HTTP2" ]; then
 		testcurl=1