Discard mail with from date older than xxxx

I know that sieve doesn't do math. The file would be created externally.

Based on examples in section 4.4 of https://tools.ietf.org/html/rfc5260#section-4

I figured something like this would work.

if date :value "le" :originalzone "date" "date" "2018-10-25" { fileinto "SPAM"; stop; }

However, I get the following.

spam: line 41: error: unknown tagged argument ':value' for the date test (reported only once at first occurrence). spam: error: validation failed. sievec(root): Fatal: failed to compile sieve script 'spam.sieve'

Does anyone have any advice on how to get this working?

Thank you.

Trever