The developers will issue several partial releases, beta releases or prereleases (which will only partially meet the specs, or specifications).
Then they will go through several rounds of updates, to remediate the deficiencies.
Remediation: act of correcting an error or a fault or an evil, http://www.synonyms.net/synonym/remediation
-- Edit -- New idea based on the clarifying comment about the testing.
The contractors will carry out several preliminary (or pre-deadline) rounds of commissioning. Subsequent to the official deadline, they will then carry out several rounds of final (or post-deadline) commissioning.
The Google definition of commission includes
Bring (something newly produced, such as a factory or machine) into working condition. We had a few hiccups getting the heating equipment commissioned.
This proposal is motivated by the commissioning I frequently hear my experimental physicist spouse talk about doing in the lab.