Release 2.4.
v1.20.0
'archived branch, refs #4170'
'archived branch, refs #4299'
'archived branch, refs #4366'
'archived branch, refs #4394'
'archived branch, refs #4395'
'archived branch, refs #4407'
'archived branch, refs #4418'
'archived branch, refs #4499'
'archived branch, refs #4577'
'archived branch, refs #4651'