Cannot install current version of php5-intl

Question

My sources are only the official Ubuntu ones:

# find /etc/apt/ -name "*.list" -exec bash -c 'printf "\n%s\n%s\n%s\n" "========" "$1" "========"; cat "$1"' _ {} \;

========
/etc/apt/sources.list
========
deb http://nl.archive.ubuntu.com/ubuntu trusty main
deb http://security.ubuntu.com/ubuntu trusty-updates main
deb http://archive.ubuntu.com/ubuntu trusty universe

And although http://packages.ubuntu.com/trusty/php5-intl says the current version of php5-intl is 5.5.9+dfsg-1ubuntu4.14 the candidate I get is 5.5.9+dfsg-1ubuntu4:

# apt-cache policy php5-intl php5-common
php5-intl:
  Installed: (none)
  Candidate: 5.5.9+dfsg-1ubuntu4
  Version table:
     5.5.9+dfsg-1ubuntu4 0
        500 http://archive.ubuntu.com/ubuntu/ trusty/universe amd64 Packages
        100 /var/lib/dpkg/status
php5-common:
  Installed: 5.5.9+dfsg-1ubuntu4.14
  Candidate: 5.5.9+dfsg-1ubuntu4.14
  Version table:
 *** 5.5.9+dfsg-1ubuntu4.14 0
        500 http://security.ubuntu.com/ubuntu/ trusty-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     5.5.9+dfsg-1ubuntu4 0
        500 http://nl.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages

Which makes that I can only install php5-intl by downgrading php5-common, which of course I don't want to do.

# apt-get update
Ign http://nl.archive.ubuntu.com trusty InRelease
Hit http://nl.archive.ubuntu.com trusty Release.gpg         
Hit http://nl.archive.ubuntu.com trusty Release             
Get:1 http://security.ubuntu.com trusty-updates InRelease [64,4 kB]
Hit http://nl.archive.ubuntu.com trusty/main amd64 Packages                    
Hit http://nl.archive.ubuntu.com trusty/main Translation-en                    
Get:2 http://security.ubuntu.com trusty-updates/main amd64 Packages [683 kB]
Ign http://nl.archive.ubuntu.com trusty/main Translation-en_ZA                
Ign http://archive.ubuntu.com trusty InRelease                                
Get:3 http://security.ubuntu.com trusty-updates/main Translation-en [342 kB]   
Hit http://archive.ubuntu.com trusty Release.gpg                               
Hit http://archive.ubuntu.com trusty Release                          
Hit http://archive.ubuntu.com trusty/universe amd64 Packages           
Hit http://archive.ubuntu.com trusty/universe Translation-en
Ign http://archive.ubuntu.com trusty/universe Translation-en_ZA             
Fetched 1 090 kB in 2s (380 kB/s)                                   
Reading package lists... Done

Answer 1

Note the [security] next to the package version - that indicates it is a security update, and available in the trusty-security repository.

You have an extremely odd configuration that enables the trusty and trusty-updates repositories, but not trusty-security. The order of importance (and safety, and dependency) is trusty, trusty-security and trusty-updates - you should have trusty-security enabled if you have trusty-updates enabled. Using http://security.ubuntu.com is not the same as enabling trusty-security, in case you are wondering. Are security.ubuntu.com updates eventually merged into normal updates?

---

By the way, there's an easier way to print the .list files you have, with filename headers:

head -n-0 /etc/apt/sources.list /etc/apt/sources.list.d/*.list