We know that the Linux kernel is written in C. What you may not know is that it is written in an old version of C: the 1989 version of the C language, version C89.
This seems to be changing:
Linus Torvalds decided that Linux will switch to the C11 standard starting with kernel 5.18.
Linus had planned to use a newer standard (version C99) but a recent update to a security issue revealed that there are problems with version C99.
Given the problems of C99, the developers agreed to use the C11 version. Backward compatibility with most compilers such as gcc should allow easy conversion of most of code.
The C89 version is still almost universally supported. So because every C compiler is compatible with older versions, there will be no problems compiling or running a program written with C89.
