The -O command-line option is deprecated. -O is a synonym for -o to output to a named file. This has been deprecated to avoid user confusion with the armcc option with the same name.

The -D command-line option is obsolete. Use --depend instead.

LDM r0!,{r0-r4} no longer ignores writeback. Previously in Thumb, LDM r0!,{r0-r4} assembled with a warning to the 16-bit LDM instruction and no writeback was performed. Because the syntax requests writeback, and this encoding is only available in Thumb-2, it produces an error. To get the 16-bit Thumb instruction you must remove the writeback.

The logical operator | is deprecated because it can cause problems with substitution of variables in source. The assembler warns on the first use of | as a logical operator. Use the :OR: operator instead.