Blues have already had the pleasure of the Berkshire-based official taking charge of one of their matches this season whilst Mr Armstrong has also refereed one Southend fixture this term.
The last time Paul Armstrong took charge of a Blues game was in our 4-1 home win against Wrexham in the 2nd Round of the League Cup in September. No Blues players were booked in the 4-1 win at St Andrew's.
The one time Paul Armstrong took charge of a Southend match this season was in their 1-0 home League defeat to Wolves in December. Alan McCormack was the only Shrimpers player booked on that occasion.
In total Paul Armstrong has refereed 19 games so far this season in which he has handed out 48 yellow cards and 3 reds.
For a detailed head-to-head between the two sides, click here