v3.1.0

Enhancements

• Decimal.new/2 now accepts an optional opts keyword list and
  forwards it to Decimal.parse/2, allowing callers to override
  :max_digits and :max_exponent when constructing a decimal from
  a string.

Bug fixes

• Fix infinite loop in Decimal.to_integer/1 when the coefficient is
  zero and the exponent is negative (e.g. Decimal.new("0.0")). Such
  values now correctly convert to the integer 0.

v2.4.1

Bug fixes

• Fix infinite loop in Decimal.to_integer/1 when the coefficient is
  zero and the exponent is negative (e.g. Decimal.new("0.0")). Such
  values now correctly convert to the integer 0.

v3.0.0

Note on the new defaults

The new decimal128 defaults are more than sufficient for currency and
other real-world numeric use cases. With precision: 34 and a scale of
2 (two digits after the decimal point for cents), values from 0.00 up
to roughly 99_999_999_999_999_999_999_999_999_999_999.99 (~10³², 100
nonillion) round-trip without rounding. Most upgrades from 2.x require
no code changes.

Security

• Make the v2.4.0 mitigations for CVE-2026-32686 the default. The
  default Decimal.Context and the public parse, cast, and to_string
  functions now follow IEEE 754 decimal128 limits, rejecting inputs
  such as 1e1000000000 without materializing them.

Breaking changes

• Decimal.Context defaults change from precision 28 and unbounded
  emax/emin to decimal128 values: precision: 34, emax: 6_144,
  emin: -6_143. Operation results whose adjusted exponent leaves that
  band signal overflow or underflow.
• Decimal.parse/1 and Decimal.cast/1 reject inputs whose digit count
  exceeds 34 (decimal128 precision) or whose absolute exponent exceeds
  6_144 (decimal128 emax). Use parse/2 / cast/2 with
  max_digits: :infinity and max_exponent: :infinity to restore
  unbounded behavior.
• Decimal.parse/2 and Decimal.cast/2 default :max_digits to 34
  and :max_exponent to 6_144 when not specified.
• Decimal.to_string/2 and Decimal.to_string/3 raise ArgumentError
  when the rendered output would exceed 6_178 digit characters
  (precision + emax — the worst-case :normal width of any in-range
  decimal128 value). Inspect, String.Chars, and JSON.Encoder
  protocol implementations pass max_digits: :infinity so debug output
  always succeeds.

v2.4.0

Security

• Mitigate exponent amplification (CVE-2026-32686).
  Compact inputs such as 1e1000000 could force multi-second expansions
  during arithmetic, parsing, normalization, comparison, or formatting.
  Decimal.add/2 and Decimal.sub/2 now scale operands to precision + 2
  digits with a sticky bit instead of materializing the full coefficient.

Enhancements

• Add :max_digits and :max_exponent options to Decimal.parse/2 and
  Decimal.cast/2 to reject pathological inputs without expansion
• Add :max_digits option to Decimal.to_string/3 to cap formatted output
  before materialization
• Add :emax and :emin fields to Decimal.Context for IBM General Decimal
  Arithmetic-style overflow and underflow signaling
• Optimize hot paths for large decimals: coef_length, normalize,
  to_integer, integer?, parsing, and large-coefficient string formatting

v2.3.0

• Implement the upcoming JSON.Encoder protocol

v2.2.0

• Add Decimal.gte?/2 and Decimal.lte?/2
• Add Decimal.compare/3 and Decimal.eq?/3 with threshold as parameter

v2.1.1

Decimal v2.1 requires Elixir v1.8+.

Bug fixes

• Fix Decimal.compare/2 when comparing against 0

v2.1.0

Decimal v2.1 requires Elixir v1.8+.

Enhancements

• Improve error message from Decimal.to_integer/1 during precision loss
• Inspect protocol implementation returns strings in the Decimal.new(...) format
• Add Decimal.scale/1
• Optimize Decimal.compare/2 for numbers with large exponents

Bug fixes

• Fix Decimal.integer?/1 spec
• Fix Decimal.integer?/1 check on 0 with >1 significant digits

v2.0.0

Decimal v2.0 requires Elixir v1.2+.

Enhancements

• Add Decimal.integer?/1

Breaking changes

• Change Decimal.compare/2 to return :lt | :eq | :gt
• Change Decimal.cast/1 to return {:ok, t} | :error
• Change Decimal.parse/1 to return {t, binary} | :error
• Remove :message and :result fields from Decimal.Error
• Remove sNaN
• Rename qNaN to NaN
• Remove deprecated support for floats in Decimal.new/1
• Remove deprecated Decimal.minus/1
• Remove deprecated Decimal.plus/1
• Remove deprecated Decimal.reduce/1
• Remove deprecated Decimal.with_context/2, Decimal.get_context/1, Decimal.set_context/1,
  and Decimal.update_context/1
• Remove deprecated Decimal.decimal?/1

v1.9.0

Enhancements

• Add Decimal.negate/1
• Add Decimal.apply_context/1
• Add Decimal.normalize/1
• Add Decimal.Context.with/2, Decimal.Context.get/1, Decimal.Context.set/2,
  and Decimal.Context.update/1
• Add Decimal.is_decimal/1

Deprecations

• Deprecate Decimal.minus/1 in favour of the new Decimal.negate/1
• Deprecate Decimal.plus/1 in favour of the new Decimal.apply_context/1
• Deprecate Decimal.reduce/1 in favour of the new Decimal.normalize/1
• Deprecate Decimal.with_context/2, Decimal.get_context/1, Decimal.set_context/2,
  and Decimal.update_context/1 in favour of new functions on the Decimal.Context module
• Deprecate Decimal.decimal?/1 in favour of the new Decimal.is_decimal/1