Deprecations

Policy

Elixir deprecations happen in 3 steps:

1. The feature is soft-deprecated. It means both CHANGELOG and documentation must list the feature as deprecated but no warning is effectively emitted by running the code. There is no requirement to soft-deprecate a feature.

2. The feature is effectively deprecated by emitting warnings on usage. In order to deprecate a feature, the proposed alternative MUST exist for AT LEAST two versions. For example, Enum.uniq/2 was soft-deprecated in favor of Enum.uniq_by/2 in Elixir v1.1. This means a deprecation warning may only be emitted by Elixir v1.3 or later.

3. The feature is removed. This can only happen on major releases. This means deprecated features in Elixir v1.x shall only be removed by Elixir v2.x.

Table of deprecations

Deprecated feature	Deprecated in	Replaced by (available since)
Atom.to_char_list/1	v1.5	Atom.to_charlist/1 (v1.3)
Enum.filter_map/3	v1.5	Enum.filter/2 + Enum.map/2 or for comprehensions (v1.0)
Float.to_char_list/1	v1.5	Float.to_charlist/1 (v1.3)
GenEvent module	v1.5	Supervisor and GenServer (v1.0); GenStage (v1.3); :gen_event (OTP 17)
Integer.to_char_list/1 and Integer.to_char_list/2	v1.5	Integer.to_charlist/1 and Integer.to_charlist/2 (v1.3)
Kernel.to_char_list/1	v1.5	Kernel.to_charlist/1 (v1.3)
List.Chars.to_char_list/1	v1.5	List.Chars.to_charlist/1 (v1.3)
Stream.filter_map/3	v1.5	Stream.filter/2 + Stream.map/2 (v1.0)
String.ljust/3 and String.rjust/3	v1.5	String.pad_leading/3 and String.pad_trailing/3 with a binary padding (v1.3)
String.strip/1 and String.strip/2	v1.5	String.trim/1 and String.trim/2 (v1.3)
String.lstrip/1 and String.rstrip/1	v1.5	String.trim_leading/1 and String.trim_trailing/1 (v1.3)
String.lstrip/2 and String.rstrip/2	v1.5	String.trim_leading/2 and String.trim_trailing/2 with a binary as second argument (v1.3)
String.to_char_list/1	v1.5	String.to_charlist/1 (v1.3)
() to mean nil	v1.5	nil (v1.0)
:as_char_lists value in Inspect.Opts.t/0 type	v1.5	:as_charlists (v1.3)
:char_lists key in Inspect.Opts.t/0 type	v1.5	:charlists (v1.3)
char_list/0 type	v1.5	charlist/0 type (v1.3)
@compile {:parse_transform, _} in Module	v1.5	None
EEx: <%= in middle and end expressions	v1.5	Use <% (= is allowed only on start expressions) (v1.0)
Access.key/1	v1.4	Access.key/2 (v1.3)
Behaviour module	v1.4	@callback (v1.0)
Enum.uniq/2	v1.4	Enum.uniq_by/2 (v1.2)
Float.to_char_list/2	v1.4	:erlang.float_to_list/2 (OTP 17)
Float.to_string/2	v1.4	:erlang.float_to_binary/2 (OTP 17)
HashDict module	v1.4	Map (v1.2)
HashSet module	v1.4	MapSet (v1.1)
Set module	v1.4	MapSet (v1.1)
Stream.uniq/2	v1.4	Stream.uniq_by/2 (v1.2)
IEx.Helpers.import_file/2	v1.4	IEx.Helpers.import_file_if_available/1 (v1.3)
Mix.Utils.camelize/1	v1.4	Macro.camelize/1 (v1.2)
Mix.Utils.underscore/1	v1.4	Macro.underscore/1 (v1.2)
Variable used as function call	v1.4	Use parentheses (v1.0)
Anonymous functions with no expression after ->	v1.4	Use an expression or explicitly return nil (v1.0)
Dict module	v1.3	Keyword (v1.0); Map (v1.2)
Keyword.size/1	v1.3	Kernel.length/1 (v1.0)
Map.size/1	v1.3	Kernel.map_size/1 (v1.0)
Set behaviour	v1.3	MapSet data structure (v1.1)
String.valid_character?/1	v1.3	String.valid?/1 (v1.0)
Task.find/2	v1.3	Use direct message matching (v1.0)
:append_first option in Kernel.defdelegate/2	v1.3	Define the function explicitly (v1.0)
/r option in Regex	v1.3	/U (v1.1)
\x{X*} inside strings/sigils/charlists	v1.3	\uXXXX or \u{X*} (v1.1)
Map or dictionary as second argument in Enum.group_by/3	v1.3	Use Enum.reduce/3 (v1.0)
Non-map as second argument in URI.decode_query/2	v1.3	Use a map (v1.0)
Dict behaviour	v1.2	MapSet data structure (v1.1)
Access protocol	v1.1	Access behaviour (v1.1)
as: true | false in alias/2 and require/2	v1.1	None
?\xHEX	v1.1	0xHEX (v1.0)
Empty string in String.starts_with?/2, String.ends_with?/2, String.contains?/2. NOTE: Feature made back available in v1.3	v1.1 to v1.2	Explicitly check for "" beforehand (v1.0)