Composer error

[praflo]

I cloned the toolkit but when I run the composer I get these errors:

$ ./composer.phar require opensrs/osrs-toolkit-php
Using version ^4.0 for opensrs/osrs-toolkit-php
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - Conclusion: remove opensrs/osrs-toolkit-php dev-master
    - Can only install one of: opensrs/osrs-toolkit-php[dev-master, 4.0.0].
    - Can only install one of: opensrs/osrs-toolkit-php[dev-master, 4.0.1].
    - Installation request for opensrs/osrs-toolkit-php dev-master -> satisfiable by opensrs/osrs-toolkit-php[dev-master].
    - Installation request for opensrs/osrs-toolkit-php ^4.0 -> satisfiable by opensrs/osrs-toolkit-php[4.0.0, 4.0.1].

Any hints on how to resolve this?
thank you
gianfranco