Paradox took a summer break for a few weeks beginning around the
24th of June 2016. In 2015, it was the
10th of July. Based on this information, we can expect the team to be targeting a release
before the summer holidays, which will be late June or early July.
We can also make some other inferences. There must be at least two more Focus Tree dev diaries. Yugoslavia and Czechoslovakia were announced, but have not yet been presented. They have announced that next week would be about equipment conversion. The free patch is going to contain an air-warfare overhaul, so we will get a DD with that topic. And we will probably get another AI update. At a stretch they could do a music / graphics update again.
Since they can combine multiple things into a single Dev Diary, I would say there is a minimum of 4 dev diaries to go, and they could stretch it out to 6 dev diaries if they needed more time. 6 weeks would take them to the 14th of June, which lines up with approximately the latest date they could release the patch and DLC while still leaving them 1-2 weeks to do a hot-fix, depending on what precise date they are going on holidays this year.