If I remember
IIR, he said he'd be out of town for a business trip this week.
|IIRC||If I remember correctly|
|AFAIR||As far as I remember|
|CRAFT||Can't remember a freakin' thing|
|DUR||Do you remember|
|CRAT||Can't remember a thing|
|CRS||Can't remember stuff|
IIR stands for "if I remember." It is both slightly shorter and much less commonly used than the similar acronym IIRC.
When you ask someone a question via online chat, forums, or email, the person answering might preface their answer with IIR. This indicates that the person is unsure whether their answer is entirely accurate, either because their knowledge is hearsay or they're possibly misremembering.