Bio Piotr is one of core developers of tranSMART from The Hyve. He was involved in several tranSMART development projects, among those: development of SmartR plugin for statistical workflows, improvements in REST-api, Glowingbear - the new UI for tranSMART and of course the 17.1 project. Before joining The Hyve Piotr worked as a Bioinformatician in the biotech industry, working mostly on scientific pipelines implementation and omics data analysis Title: Technical Overview of tranSMART 17.1 Abstract The TranSMART 17.1 development project is a large scale project organized by the tranSMART Foundation and four major pharma funding partners, Pfizer, Roche, Sanofi and AbbVie, as the tranSMART Pro Alliance. This development project, executed by bioinformatics software company The Hyve, consists from a development standpoint of three big topics: extended data support (time series, samples and crossstudy concepts), i2b2 schema alignment and refactoring. In this talk I will focus on technical aspects of the 17.1 development project and the changes it brings. One of the biggest and most challenging improvements in tranSMART is longitudinal data support. Allowing concepts to store multiple values over time requires rethinking not only the database schema but also REST api along with the consequences for the clients. Since one of the biggest priorities for the project is to preserve backward compatibility we are introducing versioning of the RESTapi. While new features is what brings value to the end users of tranSMART, our duty as the developers is also to ensure that the application is secure and that future development is not slowed down by the technical debt. This includes refactoring and dependency updates. In 17.1 we make a huge step when it comes to the tools and development workflow used. Among many changes, we introduce new build system Gradle to help manage all the subprojects of tranSMART. One of the consequences of improving the build process is a much faster and less error prone installation and development setup.