2.90 "keyword "apply_as" unrecognized" - Error Using 2.90.0 Beta, I get a
TypeError: Converting py args to operator properties: : keyword &quot;apply_as&quot; unrecognized
I believe this is coming from a Boolean modifier:
    context = bpy.context
    scene = context.scene
    tX = scene.objects.get(&quot;tX&quot;)
    tCut = scene.objects.get(&quot;tCut&quot;)
    if tX and tCut:
        bool = tX.modifiers.new(name='bool', type='BOOLEAN')
        bool.object = tCut
        bool.operation = 'DIFFERENCE'
        bpy.ops.object.modifier_apply(
                {&quot;object&quot;: tX},
                apply_as='DATA',
                modifier=bool.name)

What's interesting is it's mentioning two other python files:
Error: Traceback (most recent call last):
  File &quot;C:\Users\&quot;user&quot;\Desktop\Blender2.90\2.90\scripts\startup\panel_sidebar.py&quot;, line 131, in execute
    modifier=bool.name)
  File &quot;C:\Users\&quot;user&quot;\Desktop\Blender2.90\2.90\scripts\modules\bpy\ops.py&quot;, line 199, in __call__
    ret = op_call(self.idname_py(), C_dict, kw, C_exec, C_undo)
TypeError: Converting py args to operator properties: : keyword &quot;apply_as&quot; unrecognized

location: &lt;unknown location&gt;:-1

The panel_sidebar.py also contains the boolean function, but it wasn't being utilized. It throws a different error when it is utilized:
Error: Traceback (most recent call last):
  File &quot;\panel_sidebar.py&quot;, line 125, in execute
    bool = tX.modifiers.new(name='bool', type='BOOLEAN')
AttributeError: type object 'tX' has no attribute 'modifiers'

The ops.py has never been touched. All of this has been working fine in 2.82 &amp; 2.83. Thank you
This is not specific to boolean modifier. There was changes to python for modifiers. Remove the apply_as='DATA' and it should work.
Before we did
for data
bpy.ops.object.modifier_apply(apply_as='DATA')

for shapekey
bpy.ops.object.modifier_apply(apply_as='SHAPE')

Now we do
for data
bpy.ops.object.modifier_apply()

for apply shapekey
bpy.ops.object.modifier_apply_as_shapekey(keep_modifier=False)

for save shapekey
bpy.ops.object.modifier_apply_as_shapekey(keep_modifier=True)

To use multiple versions of Blender, you can do like this.
version = bpy.app.version

if version &gt;= (2, 91, 0):
    bpy.ops.object.modifier_apply()    
else;    
    bpy.ops.object.modifier_apply(apply_as='DATA')