In SRFI 40 we can see it is deprecated and superseded by SRFI 41. I'm using SISC where SRFI 40 is present but SRFI 41 isn't. I would like to know the main difference between them and can I use the SRFI 40 normally without fear?
SRFI-40 leaks in some circumstances. See the times3 function in the "Pitfalls" section of SRFI-41. See also the post-finalization discussion of SRFI-40.
It is possible to patch SRFI-40 to fix the problems, and some users have done so. I'm not sure if SISC has been patched. Also, David van Horn and Andre van Tonder have both made changes to the original reference implementation of SRFI-40, so I'm not sure but that may also work properly now. I personally avoid the problem and use SRFI-41.
Is there any reason SRFI-41 can't be used in SISC?
I am the author of SRFI-40 and SRFI-41.