I too saw an outage from approximately the same time however I do not see any increase in resolution.
I use both munin-evohome, and have recently set up domoticz as well - both are still showing 0.5 degree increments. Both use the version 2 API so on a hunch I did some manual tests with my munin-evohome plugin, which can be switched between V1 and V2 API's. The first is the V2 API the second is the older V1 API:
Code:
pi@pi1monitor:~ $ ./evohome_test
{'temp': 22.0, 'setpoint': 22.0, 'thermostat': 'EMEA_ZONE', 'name': u'Bathroom', 'id': u'1377389'}
{'temp': 21.0, 'setpoint': 21.0, 'thermostat': 'EMEA_ZONE', 'name': u'Living Room', 'id': u'1378782'}
{'temp': 18.5, 'setpoint': 18.0, 'thermostat': 'EMEA_ZONE', 'name': u'Main Bedroom', 'id': u'1438045'}
{'temp': 21.5, 'setpoint': 20.0, 'thermostat': 'EMEA_ZONE', 'name': u'Kitchen', 'id': u'1643296'}
{'temp': 20.5, 'setpoint': 20.0, 'thermostat': 'EMEA_ZONE', 'name': u'Hall', 'id': u'1643302'}
pi@pi1monitor:~ $ nano evohome_test
pi@pi1monitor:~ $ ./evohome_test
{'temp': 22.11, 'setpoint': 22.0, 'thermostat': u'EMEA_ZONE', 'name': u'Bathroom', 'id': 1377389}
{'temp': 20.77, 'setpoint': 20.0, 'thermostat': u'EMEA_ZONE', 'name': u'Hall', 'id': 1643302}
{'temp': 21.86, 'setpoint': 20.0, 'thermostat': u'EMEA_ZONE', 'name': u'Kitchen', 'id': 1643296}
{'temp': 21.01, 'setpoint': 21.0, 'thermostat': u'EMEA_ZONE', 'name': u'Living Room', 'id': 1378782}
{'temp': 18.98, 'setpoint': 18.0, 'thermostat': u'EMEA_ZONE', 'name': u'Main Bedroom', 'id': 1438045}
So apparently this change only applies to the (deprecated ?) V1 API at the moment!
I'll switch my munin-evohome graph plugin back to the V1 API for now, its only a one line tweak in the script to do so. (I think in the evohome-munin plugin Git repo, the V1 API is already the default, but I had changed it to V2 recently on my local copy) The domoticz plugin I don't think can be made to use the older API - anyone know ? It would be nice to get the full un-biased resolution on my Domoticz dashboard. 
BTW as well as not being rounded to 0.5 degrees it appears the figures do not have the set point bias either.
Check out the Main Bedroom temperature which says 18.5 on the rounded output with an 18 degree setpoint even though the "raw" figure is 18.98 - clearly biased towards the setpoint on the rounded figures...
I checked my controller and it is still running the same firmware, so it appears the evohome has been sending raw un-modified temperatures to the servers all along... which means all Evohome devices (evotouch controller, HR92, DTS92, honeywell servers) deal with the raw figures internally and then independently apply a setpoint bias and rounding before local display. (Or in the sever case, before returning figures via the API)
This probably explains why for example a DTS92 might consistently disagree by 0.5 degrees with the Evotouch, as their biasing/rounding algorithm might be slightly different and give a different result for the same raw value which straddles two rounded figures. I've sometimes noticed this on my DTS92.
As the phone apps use the V2 API they are currently still displaying setpoint biased rounded figures. It will be interesting to see whether increased resolution is extended to the V2 API in future.