you can specify your own paper size:

\documentclass{article}
\usepackage{geometry}
\geometry{papersize={&lt;width&gt;,&lt;height&gt;},margin=5mm}
...


Is there a document class optimized for small screens (i.e. phone screens)
When I use apt-get update and apt-get upgrade,there are some packages should installed in newest version,like below:

The following packages will be upgraded:
  accountsservice apparmor apport apt apt-transport-https apt-utils binutils
  cloud-init cpp-4.8 dpkg fuse g++-4.8 gcc-4.8 gcc-4.8-base gdisk gnupg gpgv
  grub-common grub-legacy-ec2 grub-pc grub-pc-bin grub2-common initscripts
  isc-dhcp-client isc-dhcp-common libaccountsservice0 libapparmor-perl
  libapparmor1 libapt-inst1.5 libapt-pkg4.12 libasan0 libatomic1 libbsd0
  libcurl3-gnutls libdrm2 libedit2 libfuse2 libgcc-4.8-dev libgd3 libgomp1
  libitm1 libjson-c2 libjson0 libnuma1 libpam-systemd libpolkit-agent-1-0
  libpolkit-backend-1-0 libpolkit-gobject-1-0 libquadmath0 libstdc++-4.8-dev
  libstdc++6 libsystemd-daemon0 libsystemd-login0 libtsan0 libudev1 libxext6
  linux-libc-dev ntpdate openssl overlayroot patch policykit-1 ppp
  python-urllib3 python3-apport python3-problem-report python3-update-manager
  rsyslog systemd-services sysv-rc sysvinit-utils tcpdump tzdata udev
  update-manager-core
75 upgraded, 0 newly installed, 0 to remove and 4 not upgraded.


If I didn't know every one of there packages what will happen if there update in newest version.I shouldn't execute this command(apt-get upgrade).

For example:

This php version is before I upgrade

yzxu@ubuntu:/tmp/git-2.1.2$ php --version
PHP 5.6.6-1+deb.sury.org~precise+1 (cli) 
Copyright (c) 1997-2015 The PHP Group
Zend Engine v2.6.0, Copyright (c) 1998-2015 Zend Technologies
    with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2015, by Zend Technologies


and after I upgrade:

yzxu@ubuntu:/tmp/git-2.1.2$ php --version
PHP 5.6.10-1+deb.sury.org~precise+1 (cli) 
Copyright (c) 1997-2015 The PHP Group
Zend Engine v2.6.0, Copyright (c) 1998-2015 Zend Technologies
    with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2015, by Zend Technologies


The php version is changed.And if I didn't what what was change in two version,should I upgrade it?Is it will influence product?
