Tier 2 employer letter

Hi,
I have got one query, for ILR under Tier-2 PBS, I have got employer letter but it is around 1.5 month old, can this be used. how old can the letter be dated is there some strict guidelines on this?

please advice

The SET (O) guidelines only ask for the pay slip and bank statement (showing that the pay is transferred to your account) to be within one calendar month on the day of application.

I have successfully used a letter from the employer which was about a month old.

I think, employer letter should be within one calendar month i.e., 30 days to the date of your appointment.