Update manpage date.
diff --git a/src/libiperf.3 b/src/libiperf.3
index eaf2bff..b54bb3e 100644
--- a/src/libiperf.3
+++ b/src/libiperf.3
@@ -1,4 +1,4 @@
-.TH LIBIPERF 3 "February 2018" ESnet "User Manuals"
+.TH LIBIPERF 3 "April 2018" ESnet "User Manuals"
 .SH NAME
 libiperf \- API for iperf3 network throughput tester