Adicione o repositório natty:
$sudo echo "deb http://us.archive.ubuntu.com/ubuntu/ natty main universe multiverse" >> /etc/apt/sources.list
$sudo apt-get update
Crie / etc / apt / preferences (mude o lúcido para o seu release):
Package: *
Pin: release a=natty
Pin-Priority: -10
Package: *
Pin: release a=lucid
Pin-Priority: 900
Instale o último php5-curl:
$sudo apt-get install -t natty php5-curl
Teste ( curl_version ):
$php -i | grep -i curl
cURL Information => 7.21.3
php -r 'var_dump(curl_version());'
ou faça o download do php5 e enrole os códigos fonte e crie.