Patch Package:           OTP 27.3.4.7
Git Tag:                 OTP-27.3.4.7
Date:                    2026-02-05
Trouble Report Id:       OTP-19762, OTP-19795, OTP-19830, OTP-19845,
                         OTP-19846, OTP-19890, OTP-19893, OTP-19896,
                         OTP-19926, OTP-19948, OTP-19951
Seq num:                 ERIERL-1260, ERIERL-1268, GH-10354, PR-10339,
                         PR-10358, PR-10359, PR-10437, PR-10465,
                         PR-10480, PR-10482, PR-10547, PR-10588,
                         PR-10599
System:                  OTP
Release:                 27
Application:             compiler-8.6.1.3, erts-15.2.7.5,
                         megaco-4.7.2.1, mnesia-4.23.5.1,
                         ssl-11.2.12.5, xmerl-2.1.3.3
Predecessor:             OTP 27.3.4.6

Check out the git tag OTP-27.3.4.7, and build a full OTP system including
documentation. Apply one or more applications from this build as patches to your
installation using the 'otp_patch_apply' tool. For information on install
requirements, see descriptions for each application version below.

# compiler-8.6.1.3

The compiler-8.6.1.3 application can be applied independently of other
applications on a full OTP 27 installation.

## Fixed Bugs and Malfunctions

- Fixed broken type inference for lists:mapfoldl/r.

  Own Id: OTP-19845
  Related Id(s): GH-10354, PR-10358

- Fix a compiler alias analysis bug that can generate unsafe code for repeated
  binary segments.

  Own Id: OTP-19951
  Related Id(s): PR-10588

> #### Full runtime dependencies of compiler-8.6.1.3
>
> crypto-5.1, erts-13.0, kernel-8.4, stdlib-6.0

# erts-15.2.7.5

The erts-15.2.7.5 application can be applied independently of other applications
on a full OTP 27 installation.

## Fixed Bugs and Malfunctions

- Fixed a JIT bug that could miscompile equality tests on empty bitstrings.

  Own Id: OTP-19846
  Related Id(s): PR-10359

- Fail the windows build properly when nsis is not recognised.

  Own Id: OTP-19926
  Related Id(s): PR-10547

> #### Full runtime dependencies of erts-15.2.7.5
>
> kernel-9.0, sasl-3.3, stdlib-4.1

# megaco-4.7.2.1

The megaco-4.7.2.1 application can be applied independently of other
applications on a full OTP 27 installation.

## Fixed Bugs and Malfunctions

- The megaco_tcp module had debug unintentionally enabled.

  Own Id: OTP-19896

> #### Full runtime dependencies of megaco-4.7.2.1
>
> asn1-3.0, debugger-4.0, erts-12.0, et-1.5, kernel-8.0, runtime_tools-1.8.14,
> stdlib-2.5

# mnesia-4.23.5.1

The mnesia-4.23.5.1 application can be applied independently of other
applications on a full OTP 27 installation.

## Fixed Bugs and Malfunctions

- Fixed bug where mnesia:del_table_copy/3 could fail when deleting a node that
  had tables which was not active anywhere.

  Own Id: OTP-19890
  Related Id(s): ERIERL-1268, PR-10482

> #### Full runtime dependencies of mnesia-4.23.5.1
>
> erts-9.0, kernel-5.3, stdlib-5.0

# ssl-11.2.12.5

Note! The ssl-11.2.12.5 application _cannot_ be applied independently of other
applications on an arbitrary OTP 27 installation.

       On a full OTP 27 installation, also the following runtime
       dependency has to be satisfied:
       -- public_key-1.16.4 (first satisfied in OTP 27.1.3)

## Fixed Bugs and Malfunctions

- Correct TLS-1.3 alert handling so server will always send the alert with the
  encryption keys that the client is expecting, that is if for instance if
  client certification fails the alert will be sent using application traffic
  encryption keys.

  Own Id: OTP-19795
  Related Id(s): PR-10465

- If two certificate massages are sent to the server generate an unexpected
  message alert for the second one.

  Own Id: OTP-19830
  Related Id(s): PR-10339

- Corrected app environment handling for session callback that was broken In
  OTP-23.

  Own Id: OTP-19893
  Related Id(s): PR-10480

- When preforming renegotiation, in TLS-1.2 or previous TLS versions,
  max_frag_length should not be renegotiated the connection should adhere to
  originally negotiated value, and if a value was not negotiated it shall not be
  negotiated now either.

  Own Id: OTP-19948
  Related Id(s): PR-10599

> #### Full runtime dependencies of ssl-11.2.12.5
>
> crypto-5.0, erts-15.0, inets-5.10.7, kernel-9.0, public_key-1.16.4,
> runtime_tools-1.15.1, stdlib-6.0

# xmerl-2.1.3.3

The xmerl-2.1.3.3 application can be applied independently of other applications
on a full OTP 27 installation.

## Fixed Bugs and Malfunctions

- XML regular expressions in XSD validation now handle `\s` and `\S` correctly.

  Own Id: OTP-19762
  Related Id(s): ERIERL-1260, PR-10437

> #### Full runtime dependencies of xmerl-2.1.3.3
>
> erts-6.0, kernel-8.4, stdlib-2.5

# Thanks to

Nelson Vides