diff --git a/sources b/sources
index e37f25f..effbfe0 100644
--- a/sources
+++ b/sources
@@ -1 +1 @@
-611d34844a2e9158b721e3e3daa6f127  tcl-core8.6.5-src.tar.gz
+0c818e10aa16974808f07bf83937aded  tcl-core8.6.6rc1-src.tar.gz
diff --git a/tcl.spec b/tcl.spec
index d851a82..b565787 100644
--- a/tcl.spec
+++ b/tcl.spec
@@ -1,16 +1,17 @@
+%global prerelease rc1
 %define majorver 8.6
-%define	vers %{majorver}.5
+%define	vers %{majorver}.6
 %{!?sdt:%define sdt 1}
 
 Summary: Tool Command Language, pronounced tickle
 Name: tcl
 Version: %{vers}
-Release: 1%{?dist}
+Release: 0.1%{?prerelease:.%{prerelease}}%{?dist}
 Epoch: 1
 License: TCL
 Group: Development/Languages
 URL: http://tcl.sourceforge.net/
-Source0: http://downloads.sourceforge.net/sourceforge/tcl/tcl-core%{version}-src.tar.gz
+Source0: http://downloads.sourceforge.net/sourceforge/tcl/tcl-core%{version}%{?prerelease}-src.tar.gz
 Buildrequires: autoconf
 BuildRequires: zlib-devel
 Provides: tcl(abi) = %{majorver}
@@ -140,6 +141,10 @@ rm -rf %{buildroot}/%{_datadir}/%{name}%{majorver}/ldAix
 %{_datadir}/%{name}%{majorver}/tclAppInit.c
 
 %changelog
+* Mon Jul 25 2016 Jaroslav Škarvada <jskarvad@redhat.com> - 1:8.6.6-0.1.rc1
+- New version
+  Resolves: rhbz#1359463
+
 * Tue Mar 22 2016 Jaroslav Škarvada <jskarvad@redhat.com> - 1:8.6.5-1
 - New version
   Resolves: rhbz#1313909