I'm not sure if this was a mistake or not. Persia conscription is no longer supersedes levy infantry / cavalry, which seems a little wrong, as they are two similar technologies and make sense together.
This patch restores the necessity seach levy infantry / cavalry before of conscription.
EDIT
Since we can no longer include changes to a24 (first patch), then I propose a balance of these two techs. In a23 the training decreased by 20% but a reduction of health in 5%. Mow we have a reduction of 10% of training without penalty in health. Conscription is a similar tech and cost 500 food, so 100 seems to me almost "non-existent" cost. The proposal of the patch is to increase it to 300 food and to a25 it must be a requirement for persia conscription.