Error composer install php7.0.19 pilaga 3.1.2

Hola buenos días, al realizar la instalación de las dependencias con composer y php 7 da la siguiente salida de requerimientos no cumplidos.
esto con:
Debian 9 Stertch
PHP 7.0.19-1
Composer version 1.5.6 2017-12-18 12:09:18

También ejecute el comando con la versión de composer 1.4.3 y marca los mismos requerimientos no cumplidos.

composer install
Do not run Composer as root/super user! See https://getcomposer.org/root for details
Loading composer repositories with package information
Installing dependencies (including require-dev) from lock file
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - This package requires php >=5.5 <7.0.0 but your PHP version (7.0.19) does not satisfy that requirement.
  Problem 2
    - Installation request for guiguiboy/php-cli-progress-bar dev-master -> satisfiable by guiguiboy/php-cli-progress-bar[dev-master].
    - guiguiboy/php-cli-progress-bar dev-master requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
  Problem 3
    - Installation request for mjohnson/decoda 6.10.0 -> satisfiable by mjohnson/decoda[6.10.0].
    - mjohnson/decoda 6.10.0 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
  Problem 4
    - guiguiboy/php-cli-progress-bar dev-master requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - siu-toba/framework 2.7.12 requires guiguiboy/php-cli-progress-bar dev-master -> satisfiable by guiguiboy/php-cli-progress-bar[dev-master].
    - Installation request for siu-toba/framework 2.7.12 -> satisfiable by siu-toba/framework[2.7.12].

  To enable extensions, verify that they are enabled in your .ini files:
    - /etc/php/7.0/cli/php.ini
    - /etc/php/7.0/cli/conf.d/10-opcache.ini
    - /etc/php/7.0/cli/conf.d/10-pdo.ini
    - /etc/php/7.0/cli/conf.d/15-xml.ini
    - /etc/php/7.0/cli/conf.d/20-apcu.ini
    - /etc/php/7.0/cli/conf.d/20-apcu_bc.ini
    - /etc/php/7.0/cli/conf.d/20-calendar.ini
    - /etc/php/7.0/cli/conf.d/20-ctype.ini
    - /etc/php/7.0/cli/conf.d/20-curl.ini
    - /etc/php/7.0/cli/conf.d/20-dom.ini
    - /etc/php/7.0/cli/conf.d/20-exif.ini
    - /etc/php/7.0/cli/conf.d/20-fileinfo.ini
    - /etc/php/7.0/cli/conf.d/20-ftp.ini
    - /etc/php/7.0/cli/conf.d/20-gd.ini
    - /etc/php/7.0/cli/conf.d/20-gettext.ini
    - /etc/php/7.0/cli/conf.d/20-iconv.ini
    - /etc/php/7.0/cli/conf.d/20-json.ini
    - /etc/php/7.0/cli/conf.d/20-mcrypt.ini
    - /etc/php/7.0/cli/conf.d/20-pdo_pgsql.ini
    - /etc/php/7.0/cli/conf.d/20-pgsql.ini
    - /etc/php/7.0/cli/conf.d/20-phar.ini
    - /etc/php/7.0/cli/conf.d/20-posix.ini
    - /etc/php/7.0/cli/conf.d/20-readline.ini
    - /etc/php/7.0/cli/conf.d/20-shmop.ini
    - /etc/php/7.0/cli/conf.d/20-simplexml.ini
    - /etc/php/7.0/cli/conf.d/20-sockets.ini
    - /etc/php/7.0/cli/conf.d/20-sysvmsg.ini
    - /etc/php/7.0/cli/conf.d/20-sysvsem.ini
    - /etc/php/7.0/cli/conf.d/20-sysvshm.ini
    - /etc/php/7.0/cli/conf.d/20-tokenizer.ini
    - /etc/php/7.0/cli/conf.d/20-wddx.ini
    - /etc/php/7.0/cli/conf.d/20-xmlreader.ini
    - /etc/php/7.0/cli/conf.d/20-xmlwriter.ini
    - /etc/php/7.0/cli/conf.d/20-xsl.ini
    - /etc/php/7.0/cli/conf.d/20-zip.ini
  You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.

Luego en la web de composer vi que se puede realizar " composer install --ignore-platform-reqs " de la siguiente manera.
Queríamos saber si puede presentar un problema en la instalación de pilaga.

composer install --ignore-platform-reqs
Do not run Composer as root/super user! See https://getcomposer.org/root for details
Loading composer repositories with package information
Installing dependencies (including require-dev) from lock file
Package operations: 51 installs, 0 updates, 0 removals
  - Installing doctrine/lexer (v1.0.1): Downloading (100%)
  - Installing firebase/php-jwt (v4.0.0): Downloading (100%)
  - Installing clue/graph (v0.9.0): Downloading (100%)
  - Installing graphp/algorithms (v0.8.1): Downloading (100%)
  - Installing graphp/graphviz (v0.2.1): Downloading (100%)
  - Installing react/promise (v2.5.1): Downloading (100%)
  - Installing guzzlehttp/streams (3.0.0): Downloading (100%)
  - Installing guzzlehttp/ringphp (1.1.0): Downloading (100%)
  - Installing symfony/yaml (v3.1.3): Downloading (100%)
  - Installing incenteev/composer-parameter-handler (v2.1.2): Downloading (100%)
  - Installing ircmaxell/security-lib (v1.1.0): Downloading (100%)
  - Installing ircmaxell/random-lib (dev-master e9e0204): Cloning e9e0204f40 from cache
  - Installing psr/container (1.0.0): Downloading (100%)
  - Installing siu-si/xlib (v1.0.7): Cloning cad4cbc82f from cache
  - Installing zendframework/zend-escaper (2.4.10): Downloading (100%)
  - Installing zendframework/zend-stdlib (2.4.13): Downloading (100%)
  - Installing zendframework/zend-validator (2.4.13): Downloading (100%)
  - Installing zendframework/zend-uri (2.4.13): Downloading (100%)
  - Installing mjohnson/decoda (6.10.0): Downloading (100%)
  - Installing michelf/php-markdown (1.7.0): Downloading (100%)
  - Installing ezyang/htmlpurifier (v4.9.3): Downloading (100%)
  - Installing siu/security-multitool (v1.0.1): Cloning 79857a03eb from cache
  - Installing seld/jsonlint (1.6.1): Downloading (100%)
  - Installing justinrainbow/json-schema (1.6.1): Downloading (100%)
  - Installing siu/json-util (v1.3): Cloning d3ad9a78e5 from cache
  - Installing siu/arai-json-migrator (v1.0.1): Cloning b1a6f2f3cd from cache
  - Installing psr/log (1.0.2): Downloading (100%)
  - Installing symfony/debug (v2.8.28): Downloading (100%)
  - Installing symfony/polyfill-mbstring (v1.6.0): Downloading (100%)
  - Installing symfony/console (v2.8.28): Downloading (100%)
  - Installing siu/arai-json-parser (v1.0.0): Cloning 9a96f8f85c from cache
  - Installing seld/cli-prompt (1.0.3): Downloading (100%)
  - Installing pimple/pimple (v3.2.2): Downloading (100%)
  - Installing monolog/monolog (1.23.0): Downloading (100%)
  - Installing guzzlehttp/guzzle (5.1.0): Downloading (100%)
  - Installing egulias/email-validator (1.2.14): Downloading (100%)
  - Installing siu/arai-cli (v1.1.8): Cloning 3ad48ab039 from cache
  - Installing siu-toba/ssl-cert-utils (v1.0): Downloading (100%)
  - Installing siu-toba/jwt-util (v1.0.2): Downloading (100%)
  - Installing doctrine/cache (v1.6.2): Downloading (100%)
  - Installing siu-toba/rest (v1.1.8): Downloading (100%)
  - Installing onelogin/php-saml (2.3.0): Downloading (100%)
  - Installing guiguiboy/php-cli-progress-bar (dev-master 7d3eb61): Cloning 7d3eb61c1f from cache
  - Installing siu-toba/framework (2.7.12):  Checking out /versiones/2.7.12/@7071
  - Installing vlucas/phpdotenv (v2.4.0): Downloading (100%)
  - Installing symfony/process (v3.3.10): Downloading (100%)
  - Installing symfony/finder (v3.3.10): Downloading (100%)
  - Installing symfony/filesystem (v3.3.10): Downloading (100%)
  - Installing siu/check-constraints (v1.0.3): Cloning 59b7938486 from cache
  - Installing siu/instalador (v1.0.7): Cloning 4cff7062a7 from cache
  - Installing siu/toba-db (v1.0.3): Cloning 392c2151bd from cache
zendframework/zend-stdlib suggests installing zendframework/zend-eventmanager (To support aggregate hydrator usage)
zendframework/zend-stdlib suggests installing zendframework/zend-filter (To support naming strategy hydrator usage)
zendframework/zend-stdlib suggests installing zendframework/zend-serializer (Zend\Serializer component)
zendframework/zend-stdlib suggests installing zendframework/zend-servicemanager (To support hydrator plugin manager usage)
zendframework/zend-validator suggests installing zendframework/zend-db (Zend\Db component)
zendframework/zend-validator suggests installing zendframework/zend-filter (Zend\Filter component, required by the Digits validator)
zendframework/zend-validator suggests installing zendframework/zend-i18n (Zend\I18n component to allow translation of validation error messages as well as to use the various Date validators)
zendframework/zend-validator suggests installing zendframework/zend-math (Zend\Math component)
zendframework/zend-validator suggests installing zendframework/zend-resources (Translations of validator messages)
zendframework/zend-validator suggests installing zendframework/zend-servicemanager (Zend\ServiceManager component to allow using the ValidatorPluginManager and validator chains)
zendframework/zend-validator suggests installing zendframework/zend-session (Zend\Session component)
mjohnson/decoda suggests installing ext-memcached (Cache data using Memcache)
mjohnson/decoda suggests installing ext-redis (Cache data using Redis)
symfony/polyfill-mbstring suggests installing ext-mbstring (For best performance)
symfony/console suggests installing symfony/event-dispatcher ()
monolog/monolog suggests installing aws/aws-sdk-php (Allow sending log messages to AWS services like DynamoDB)
monolog/monolog suggests installing doctrine/couchdb (Allow sending log messages to a CouchDB server)
monolog/monolog suggests installing ext-amqp (Allow sending log messages to an AMQP server (1.0+ required))
monolog/monolog suggests installing ext-mongo (Allow sending log messages to a MongoDB server)
monolog/monolog suggests installing graylog2/gelf-php (Allow sending log messages to a GrayLog2 server)
monolog/monolog suggests installing mongodb/mongodb (Allow sending log messages to a MongoDB server via PHP Driver)
monolog/monolog suggests installing php-amqplib/php-amqplib (Allow sending log messages to an AMQP server using php-amqplib)
monolog/monolog suggests installing php-console/php-console (Allow sending log messages to Google Chrome)
monolog/monolog suggests installing rollbar/rollbar (Allow sending log messages to Rollbar)
monolog/monolog suggests installing ruflin/elastica (Allow sending log messages to an Elastic Search server)
monolog/monolog suggests installing sentry/sentry (Allow sending log messages to a Sentry server)
siu/check-constraints suggests installing siu/toba-ldap (Permite realizar chequeos a un servicio LDAP)
Generating autoload files

Muchas Gracias saludos.

Buenas tardes,

Actualmente hasta la versión 3.1.2 de pilaga los requerimientos para PHP son (>=5.5 o <7.0.0) esa información esta en la documentación.
El sistema esta desarrollado y probado para ese rango de versiones de PHP, por tal motivo no se recomienda forzar la instalación del composer ni del sistema con versiones de PHP que no están soportadas hasta el momento.

Saludos,

Muchas Gracias es el dato que necesitaba.

Saludos.