In 2016, the texas supreme court held that the existing system for funding public schools met the minimum constitutional provisions for

The answer to the question is pretty much in the question itself. At issue was whether the funding system for public schools in Texas was meeting the minimum constitutional standard for funding public schools, and the court said yes. The legal challenges to the funding plan were claims like:

... The funding provided by the Legislature was insufficient to ensure that students would meet academic standards.

... Large differences in funding were seen between rich and poor school districts. (Rich and poor based on property values, and property taxes were the main funding mechanism for schools.)

The funding system passed at the Texas Supreme Court level, but barely. There generally remains a feeling that more must be done to fund all schools more adequately, but at least the bare minimum was seen (by the court) as being done.