In the POSIXly-correct mode, the standard input of an asynchronous list was automatically redirected to /dev/null if the shell was interactive. POSIX now requires such redirection for non-job-controlling shells rather than interactive shells. The new behavior matches the non-POSIXly-correct mode.
POSIX no longer requires SIGINT and SIGQUIT of an asynchronous list be ignored if the list is job-controlled. This also matches the non-POSIXly-correct mode.
In the POSIXly-correct mode, the standard input of an asynchronous list was automatically redirected to /dev/null if the shell was interactive. POSIX now requires such redirection for non-job-controlling shells rather than interactive shells. The new behavior matches the non-POSIXly-correct mode.
http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_09_03_02
POSIX no longer requires SIGINT and SIGQUIT of an asynchronous list be ignored if the list is job-controlled. This also matches the non-POSIXly-correct mode.
http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_11