I am not with Laminar Research; just a flight simmer.
To run a DVD version of X-Plane you have to have disc 1 inserted in the DVD drive at all times when running X-Plane. If not it will automatically revert to the demo mode.
As indicated by Thomson (Laminar Research) there is a beta version of X-Plane available.
The latest official public release version of X-Plane is 11.26 which you have.
The official public release version of X-Plane 11.30 is to be released in the near future. Until that happens beta versions are released for those who have an intimate knowledge base on how X-Plane works. When a beta version is released it is made available to a selected few for "private" testing.
The next stage is general public beta release for those knowledgeable users This is the current progress for updates mentioned by Thomson
When Laminar Research is satisfied their appears to be no more issues after all of the beta testing, the official public release version of X-plane will be made available for the general flight sim user. An overall lengthy process.
Bottom line is you have the current official version of X-Plane. If you are one of the knowledgeable few and want to dabble with the current Beta version then download. Otherwise sit back and wait for the official release of 11.30.
As a sideline issue are you a steam user? Steam is a 3rd party hybrid version of x-plane and does not mix with the official version of x-plane created by Laminar Research. There has been several instances in this forum whereby steam users want to update. Steam does not make beta versions available and only updates once the official Laminar Research version has been released. The updates from steam are several days after the release by Laminar.