I found the answer on the CIC web; 0 B2 w3 n& ^! y( R/ d9 H4 `9 ]"The certificate must have been issued no more than three months before you submit your application" ! [- k4 e4 {' V; F& v% R8 M* b" O" T: {% O# A7 i. A2 f7 X. R
Ours were more than one year when we applied.