diff --git a/ntp-server.spec b/ntp-server.spec
index b10cbac..aa639d6 100644
--- a/ntp-server.spec
+++ b/ntp-server.spec
@@ -1,13 +1,13 @@
 %define majver %(echo %version | cut -d. -f1-2)
 Name:          ntp-server
 Version:       4.2.8p15
-Release:       2mamba
+Release:       4mamba
 Summary:       Synchronizes system time using the Network Time Protocol (NTP)
 Group:         System/Configuration
 Vendor:        openmamba
 Distribution:  openmamba
 Packager:      Silvan Calarco <silvan.calarco@mambasoft.it>
-URL:           http://www.ntp.org
+URL:           https://www.ntp.org
 Source0:       https://www.eecis.udel.edu/~ntp/ntp_spool/ntp4/ntp-%{majver}/ntp-%{version}.tar.gz
 Source1:       ntp.conf
 Source2:       ntp.keys
@@ -52,7 +52,7 @@ BuildRequires: perl-IO-Socket-SSL
 BuildRequires: perl-Net-SSLeay
 BuildRequires: perl-devel
 ## AUTOBUILDREQ-END
-BuildRoot:     %{_tmppath}/%{name}-%{version}-root
+BuildRequires: librpm-devel >= 4.16.1.2-1mamba
 
 %description
 The Network Time Protocol (NTP) is used to synchronize a computer's time with another reference time source.
@@ -162,6 +162,12 @@ install -D -m644 %{S:8} %{buildroot}%{_unitdir}/ntpdate.service
 #%doc ChangeLog NEWS *.y2kfixes README* TODO WHERE-TO-START
 
 %changelog
+* Mon Mar 08 2021 Silvan Calarco <silvan.calarco@mambasoft.it> 4.2.8p15-4mamba
+- rebuilt to fix requirements in /bin
+
+* Sun Mar 07 2021 Silvan Calarco <silvan.calarco@mambasoft.it> 4.2.8p15-3mamba
+- rebuilt by autoport with build requirements: librpm-devel>=4.16.1.2-1mamba
+
 * Sun Feb 28 2021 Silvan Calarco <silvan.calarco@mambasoft.it> 4.2.8p15-2mamba
 - fix ntpd path in service files