sudo apt-get update gives following error

Saucy has only a week or so of support left. You may want to upgrade soon.

I didn't get it what you said??

https://wiki.ubuntu.com/Releases

http://www.sysads.co.uk/2014/06/ubuntu-13-10-saucy-salamander-reaching-end-of-life-on-july-17-2014/

After Saucy goes end of lifr (EOL) there will be zero updates and zero community support.

You may want to take this opportunity to upgrade to Trusty. Trusty is longterm supported (LTS) and is supported til April 2019.

Do i need to upgrade my OS??

even while updating i am getting same error..

what is the full output of:

sudo apt-get clean
sudo apt-get update
sudo apt-get upgrade

Thanks

After running apt-get clean:
nothing

After running sudo apt-get update:
E: Some index files failed to download. They have been ignored, or old ones used instead.

After running sudo apt-get upgrade:
The following packages have unmet dependencies:
 gnome-user-guide : Depends: yelp (>= 3) but it is not installed
 lintian : Depends: man-db
 php-gettext : Depends: php5 but it is not installed or
                        php5-cli but it is not installed
 phpmyadmin : Depends: libapache2-mod-php5 but it is not installed or
                       libapache2-mod-php5filter but it is not installed or
                       php5-cgi but it is not installed or
                       php5-fpm but it is not installed or
                       php5 but it is not installed
              Depends: php5-mysql but it is not installed or
                       php5-mysqli but it is not installable or
                       php5-mysqlnd but it is not installed
              Recommends: php5-gd but it is not installed
 ubuntu-standard : Depends: man-db
E: Unmet dependencies. Try using -f.

And when i run
sudo apt-get install -f;

i got following error:
Use of uninitialized value in concatenation (.) or string at /usr/share/perl5/Debconf/DbDriver/File.pm line 44, <DEBCONF_CONFIG> chunk 3.
Use of uninitialized value in -e at /usr/share/perl5/Debconf/DbDriver/File.pm line 46, <DEBCONF_CONFIG> chunk 3.
Use of uninitialized value in pattern match (m//) at /usr/share/perl5/Debconf/DbDriver/File.pm line 47, <DEBCONF_CONFIG> chunk 3.
Use of uninitialized value $directory in -d at /usr/share/perl5/Debconf/DbDriver/File.pm line 48, <DEBCONF_CONFIG> chunk 3.
Use of uninitialized value $directory in concatenation (.) or string at /usr/share/perl5/Debconf/DbDriver/File.pm line 49, <DEBCONF_CONFIG> chunk 3.
debconf: DbDriver "config": mkdir :No such file or directory
Setting up tzdata (2014e-0ubuntu0.13.10) ...
Use of uninitialized value in concatenation (.) or string at /usr/share/perl5/Debconf/DbDriver/File.pm line 44, <DEBCONF_CONFIG> chunk 3.
Use of uninitialized value in -e at /usr/share/perl5/Debconf/DbDriver/File.pm line 46, <DEBCONF_CONFIG> chunk 3.
Use of uninitialized value in pattern match (m//) at /usr/share/perl5/Debconf/DbDriver/File.pm line 47, <DEBCONF_CONFIG> chunk 3.
Use of uninitialized value $directory in -d at /usr/share/perl5/Debconf/DbDriver/File.pm line 48, <DEBCONF_CONFIG> chunk 3.
Use of uninitialized value $directory in concatenation (.) or string at /usr/share/perl5/Debconf/DbDriver/File.pm line 49, <DEBCONF_CONFIG> chunk 3.
debconf: DbDriver "config": mkdir :No such file or directory
dpkg: error processing tzdata (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 tzdata
E: Sub-process /usr/bin/dpkg returned an error code (1)

Please help asap

Please try the solution procedure here:

https://answers.launchpad.net/ubuntu/+source/update-manager/+question/166843

Post all output here:

https://answers.launchpad.net/ubuntu/+source/php5/+question/251231