David T. Lewis uploaded a new version of Chronology-Core to project The Trunk:
http://source.squeak.org/trunk/Chronology-Core-dtl.38.mcz

==================== Summary ====================

Name: Chronology-Core-dtl.38
Author: dtl
Time: 27 January 2019, 1:21:28.699596 pm
UUID: 1b64f41b-a799-4f9d-9037-cab677271baa
Ancestors: Chronology-Core-dtl.33

Change DateAndTime>>makeUTC to behave as in prior versions of Chronology, and expand its comment to explain that both magniitude and timezone offset are changed in the receiver. Update DateAndTime>>asUTC to avoid use of makeUTC.Fixes three failing unit tests.

=============== Diff against Chronology-Core-dtl.33 ===============

Item was changed:
  ----- Method: DateAndTime>>asUTC (in category 'ansi protocol') -----
  asUTC
  
  	localOffsetSeconds = 0 ifTrue: [ ^self ].
+ 	^self copy localOffsetSeconds: 0.!
- 	^self copy makeUTC!

Item was changed:
  ----- Method: DateAndTime>>makeUTC (in category 'squeak protocol') -----
  makeUTC
+ 	"Make the receiver's timezone UTC. This adjusts both the magnitude and
+ 	local offset of the receiver such that self asString remains unchanged
+ 	except for a zero timezone offset."
+ 
+ 	^ self
+ 		utcMicroseconds: localOffsetSeconds * 1000000 + utcMicroseconds
+ 		offset: 0
+ !
- 	"Make the receiver's timezone UTC."
- 	localOffsetSeconds := 0!