use readme from 4.2.1 branch

README.md

@@ -42,11 +42,12 @@ The --device=/dev/dvb is only needed if you want to pass through a DVB card to t
 
 You can choose between ,using tags, latest (default, and no tag required or a specific stable version of tvheadend.
 
-Add one of the tags, if required, to the linuxserver/tvheadend line of the run/create command in the following format, linuxserver/tvheadend:stable-4.0.9
+Add one of the tags, if required, to the linuxserver/tvheadend line of the run/create command in the following format, linuxserver/tvheadend:stable-4.2.1
 
 #### Tags
 
-+ **stable-4.0.9** : latest stable version.
++ **stable-4.2.1** : latest stable version.
++ **stable-4.0.9** : old stable version. Will not be updated anymore!
 
 #### Host vs. Bridge
 
@@ -151,6 +152,7 @@ You need to enable minimum advanced view level to see the picons options.
 
 ## Versions
 
++ **01.05.2017:** Update to tvheadend 4.2.1 stable.
 + **18.04.2017:** Use repo version of gnu-libiconv rather than compiling.
 + **09.04.2017:** Chain cpanm installs in one block and use --installdeps.
 + **09.02.2017:** Perl changes, add picons file to gitignore and update XMLTV to 0.5.69.