I succeeded in installing Mojave with e7240. I thank all the participants of this wonderful forum.
Both audio and WiFi are running smoothly. Bluetooth does not work, but it is natural. Because Hervé is recommending replacing, as follows.
My procedure is very simple.
1) First of all, read Hervé's post carefully.
2) Next, follow the great content of Jake Lo.
* My Kext referred to the contents of this article. *
Please let me express my sincere gratitude once again.