Assuming we don't want a completely new thread for Season 15/16 - just a bit of a pain having to correct the thread title each time - hint, hint, mods?  
 KC Royal 
Anyone know when the fixtures usually come out?
...as a rough guide here's last seasons' NL fixture publication dates:
Levels 1-4: 18 June - so that's Prem, Chumps & FL1+2 - in newer 'old money'!  
 Conference: 4 July 
...apparently the date for this coming season of the 1st July - was picked up came from Southport's forum - not sure where they got it from.
As for the title "NATIONAL League" as it will be known, I'm not sure how long before the CONFERENCE tag will be dropped - probably be around a long time informally. Is bit of a strange thing to cope with - 
 at STEPS1 & 2 we may have to refer to the NATIONAL NATIONAL; NATIONAL NORTH & NATIONAL SOUTH  
 ) Southern League should be on or around 13th July - probably close to the 
Ryman/Isthmian (Lewes have proffered this same date as likely) - though there are still a few unresolved reprieves at STEP04 and another couple of fairly local clubs very close to extinction. 
Leighton Town being the latest focus of attention - usual tale; manager and entire squad rumoured to have walked and no more income from the club from 
Aylesbury Utd - who have upped sticks and moved in with 
Thame for next season.
- this would of course impact on constitutional line ups of the CCL, HELLENIC & South Mids and there are several proposed 'switches'  that might need revisiting, should Leighton 'go under'.
I might throw the known line-ups out in a week or two should anything get decided in the meantime - there are a couple of 'draft' line-ups about but a few relegation issues at STEP04 remain uncertain. There are also a some surprising constitutional club Transfers in the offing - mostly involving Southern League clubs - e.g. reportedly 
Burnham, Marlow (and 
Flackwell) have been switched to/placed in SL Div One South & West for 15/16.
There are also unexpected enforced 'grading' demotions which may change things still further :
- one example :reportedly 
Clevedon Town (down nr Brizzle) have had the lights at their Hand Stadium de-classified and face demotion or extinction (the current 'lux' rating or whatever they go by - would not even meet Western League entry standards)
Hallen  similarly face expulsion/closure - though I think that may be due to  'falling out with the Social Club/Local Authority' syndrome.  

  - shame nice ground round the Western side of Brizzle - 
tricky to get to and they couldn't find anyone to run the bar at H/T when I visited a few years back....   
  They could always move in with Cribbs who are about a mile down the road.