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curl / Development / Deprecate
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Items to be removed from future curl releases

If any of these deprecated features is a cause for concern for you, please email the curl-library mailing list as soon as possible and explain to us why this is a problem for you and how your use case cannot be satisfied properly using a workaround.

c-ares 1.16.0

In March 2026, we drop support for all c-ares versions before 1.16.0.

RTMP

RTMP in curl is powered by the 3rd party library librtmp.

Support for RTMP in libcurl gets removed in April 2026.

CMake 3.17 and earlier

We remove support for CMake <3.18 in April 2026.

CMake 3.18 was released on 2020-07-15.

TLS-SRP Authentication

Transport Layer Security Secure Remote Password is a TLS feature that does not work with TLS 1.3 or QUIC and is virtually unused by curl users and in general.

TLS-SRP support gets removed in August 2026.

SMB goes opt-in

The SMB protocol has weak security and is rarely used these days. After curl 8.19.0 SMB support becomes opt-in.

NTLM goes opt-in

The NTLM authentication method has weak security and is rarely used these days. It has been deprecated by Microsoft and does not work over HTTP/2 or HTTP/3.

After curl 8.19.0 NTLM support becomes opt-in.

Past removals