My output of $ running brew update && brew upgrade && brew install php55 - per homebrew-php upgrade issues instructions.

gistfile1.txt

$ brew update && brew upgrade && brew install php55
Already up-to-date.
==> Upgrading 5 outdated packages, with result:
couchdb 1.6.0_1, git 2.1.0, icu4c 53.1, mongodb 2.6.4, node 0.10.31
==> Upgrading couchdb
==> Installing couchdb dependency: icu4c
==> Downloading https://downloads.sf.net/project/machomebrew/Bottles/icu4c-53.1.mavericks.bottle.tar.gz
######################################################################## 100.0%
==> Pouring icu4c-53.1.mavericks.bottle.tar.gz
==> Caveats
This formula is keg-only, which means it was not symlinked into /usr/local.

Conflicts; see: https://github.com/Homebrew/homebrew/issues/issue/167

Generally there are no consequences of this for you. If you build your
own software and it requires this formula, you'll need to add to your
build variables:

    LDFLAGS:  -L/usr/local/opt/icu4c/lib
    CPPFLAGS: -I/usr/local/opt/icu4c/include

==> Summary
🍺  /usr/local/Cellar/icu4c/53.1: 241 files, 57M
==> Installing couchdb
==> Downloading https://downloads.sf.net/project/machomebrew/Bottles/couchdb-1.6.0_1.mavericks.bottle.tar.gz
######################################################################## 100.0%
==> Pouring couchdb-1.6.0_1.mavericks.bottle.tar.gz
==> Caveats
To test CouchDB run:
    curl http://127.0.0.1:5984/

The reply should look like:
    {"couchdb":"Welcome","uuid":"....","version":"1.6.0","vendor":{"version":"1.6.0-1","name":"Homebrew"}}

To have launchd start couchdb at login:
    ln -sfv /usr/local/opt/couchdb/*.plist ~/Library/LaunchAgents
Then to load couchdb now:
    launchctl load ~/Library/LaunchAgents/homebrew.mxcl.couchdb.plist
Or, if you don't want/need launchctl, you can just run:
    couchdb
==> Summary
🍺  /usr/local/Cellar/couchdb/1.6.0_1: 636 files, 16M
==> Upgrading git
==> Downloading https://downloads.sf.net/project/machomebrew/Bottles/git-2.1.0.mavericks.bottle.tar.gz
######################################################################## 100.0%
==> Pouring git-2.1.0.mavericks.bottle.tar.gz
==> Caveats
The OS X keychain credential helper has been installed to:
  /usr/local/bin/git-credential-osxkeychain

The 'contrib' directory has been installed to:
  /usr/local/share/git-core/contrib

Bash completion has been installed to:
  /usr/local/etc/bash_completion.d

zsh completion has been installed to:
  /usr/local/share/zsh/site-functions
==> Summary
🍺  /usr/local/Cellar/git/2.1.0: 1339 files, 31M
==> Upgrading mongodb
==> Downloading https://downloads.sf.net/project/machomebrew/Bottles/mongodb-2.6.4.mavericks.bottle.tar.gz
######################################################################## 100.0%
==> Pouring mongodb-2.6.4.mavericks.bottle.tar.gz
==> Caveats
To have launchd start mongodb at login:
    ln -sfv /usr/local/opt/mongodb/*.plist ~/Library/LaunchAgents
Then to load mongodb now:
    launchctl load ~/Library/LaunchAgents/homebrew.mxcl.mongodb.plist
Or, if you don't want/need launchctl, you can just run:
    mongod --config /usr/local/etc/mongod.conf
==> Summary
🍺  /usr/local/Cellar/mongodb/2.6.4: 17 files, 319M
==> Upgrading node
==> Downloading https://downloads.sf.net/project/machomebrew/Bottles/node-0.10.31.mavericks.bottle.tar.gz
######################################################################## 100.0%
==> Pouring node-0.10.31.mavericks.bottle.tar.gz
==> Caveats
Bash completion has been installed to:
  /usr/local/etc/bash_completion.d
Error: The `brew link` step did not complete successfully
The formula built, but is not symlinked into /usr/local
Could not symlink include/node/ares.h
Target /usr/local/include/node/ares.h
already exists. You may want to remove it:
  rm /usr/local/include/node/ares.h

To force the link and overwrite all conflicting files:
  brew link --overwrite node

To list all files that would be deleted:
  brew link --overwrite --dry-run node

Possible conflicting files are:
/usr/local/include/node/ares.h
/usr/local/include/node/ares_version.h
/usr/local/include/node/common.gypi
/usr/local/include/node/config.gypi
/usr/local/include/node/nameser.h
/usr/local/include/node/node.h
/usr/local/include/node/node_buffer.h
/usr/local/include/node/node_internals.h
/usr/local/include/node/node_object_wrap.h
/usr/local/include/node/node_version.h
/usr/local/include/node/openssl/opensslconf.h
/usr/local/include/node/uv-private/ngx-queue.h
/usr/local/include/node/uv-private/stdint-msvc2008.h
/usr/local/include/node/uv-private/tree.h
/usr/local/include/node/uv-private/uv-bsd.h
/usr/local/include/node/uv-private/uv-darwin.h
/usr/local/include/node/uv-private/uv-linux.h
/usr/local/include/node/uv-private/uv-sunos.h
/usr/local/include/node/uv-private/uv-unix.h
/usr/local/include/node/uv-private/uv-win.h
/usr/local/include/node/uv.h
/usr/local/include/node/v8-debug.h
/usr/local/include/node/v8-preparser.h
/usr/local/include/node/v8-profiler.h
/usr/local/include/node/v8-testing.h
/usr/local/include/node/v8.h
/usr/local/include/node/v8stdint.h
/usr/local/include/node/zconf.h
/usr/local/include/node/zlib.h
==> make install
==> /usr/local/bin/npm update npm -g --prefix /usr/local
==> Summary
🍺  /usr/local/Cellar/node/0.10.31: 1547 files, 19M
==> Downloading http://www.php.net/get/php-5.5.15.tar.bz2/from/this/mirror
Already downloaded: /Library/Caches/Homebrew/php55-5.5.15
Warning: Backing up all known pear.conf and .pearrc files
Warning: If you have a pre-existing pear install outside
         of homebrew-php, or you are using a non-standard
         pear.conf location, installation may fail.
==> ./configure --prefix=/usr/local/Cellar/php55/5.5.15 --localstatedir=/usr/local/var --sysconfdir=/usr/local/etc/php/5.5 --with-config-file-path=/usr/local/etc/php/5.5 --with-con
==> make
==> make install
==> /usr/local/Cellar/php55/5.5.15/bin/pear config-set php_ini /usr/local/etc/php/5.5/php.ini
==> Caveats
To enable PHP in Apache add the following to httpd.conf and restart Apache:
    LoadModule php5_module    /usr/local/opt/php55/libexec/apache2/libphp5.so

The php.ini file can be found in:
    /usr/local/etc/php/5.5/php.ini

✩✩✩✩ PEAR ✩✩✩✩

If PEAR complains about permissions, 'fix' the default PEAR permissions and config:
    chmod -R ug+w /usr/local/Cellar/php55/5.5.15/lib/php
    pear config-set php_ini /usr/local/etc/php/5.5/php.ini

✩✩✩✩ Extensions ✩✩✩✩

If you are having issues with custom extension compiling, ensure that
you are using the brew version, by placing /usr/local/bin before /usr/sbin in your PATH:

      PATH="/usr/local/bin:$PATH"

PHP55 Extensions will always be compiled against this PHP. Please install them
using --without-homebrew-php to enable compiling against system PHP.

✩✩✩✩ PHP CLI ✩✩✩✩

If you wish to swap the PHP you use on the command line, you should add the following to ~/.bashrc,
~/.zshrc, ~/.profile or your shell's equivalent configuration file:

      export PATH="$(brew --prefix homebrew/php/php55)/bin:$PATH"

To have launchd start php55 at login:
    ln -sfv /usr/local/opt/php55/*.plist ~/Library/LaunchAgents
Then to load php55 now:
    launchctl load ~/Library/LaunchAgents/homebrew.mxcl.php55.plist
==> Summary
🍺  /usr/local/Cellar/php55/5.5.15: 493 files, 39M, built in 9.8 minutes