SA 315 is applicable.
SA 315 says internal control system “may be” checked once in 3 years.
Gap between checking ICS “must not be” more than 2 years.
Whether to check ICS again in current year depends on factors given in SA 315 (To understand below points you will have to watch video of SA 315)
–Changes in ICS
–Personnel Changes & Effectiveness of ICS
–Manual Vs Automated Controls
— Risk of Material Misstatement
— Control Enviornment
— General IT Controls