Version 4 is an almost total rewrite of the previous glorious version 3 that has been around since 2013. In these many years multiple features have been added and many buges have been fixed, making v3 extremly stable and reliable. It is currently used in production by almost 30 international research projects focusing on archaeology and cultural heritage.
Yet, since nothing is forever, it is time to start a gradual migration towards version 4, which is the right path towards the future. At present, a great work has been done in porting all the features of the v3 to the new one and we are almost done!
A very important new feature of v4 is the support for other database engines other then sqlite. Currently MySQL (and thus MariaDB and PerconaDB) and PostgreSQL are supported. This comes at some cost: possible bugs and a stricter adhesion to Standard SQL.
Version 4 makes exclusive usage of ShortSQL language to query the database. Since ShortSQL permits a very granularvalidation of the input data, allowing a high flexibiluty and query power, the v4 API reaches a high degree of security. In the first stable release of v4, API v1, deprecated since 2022-01-14 will be removed. API versioning will be also removed and the API will follow the main versioning pattern.
The whole PHP code has been rewritten trying not to change the main API, debugging and improving the current functionalities. namespaces, strongly typed PHP code and whitespread usage of inline documentation will help collaboration anf further development. The update of all dependencies, both PHP and JS, also improve security.
Before releasing the v4, some more testing and bug-fixing is required. Also the multiplication of the available database engines, make testing and debugging much more complex and time-consuming. Also some web-applications already available making wide usage of the API v1 must be migrated in order to fully comply with the newest version.