Changelog for C SDK

## 1.0.0 *September 21, 2026* | Type | Changes | |------|----------| | **Added** | • Ground-up rewrite of the PubNub C SDK: a platform-neutral C11 core (with a C99 compatibility mode) built around six pluggable provider families — transport, serialization, crypto, allocator, logger, and platform.<br/>• Multi-context architecture with no static or global per-context state; multiple independent client contexts operate concurrently in a single process.<br/>• Pluggable HTTP transport providers: a libcurl-backed backend for hosted platforms and a native BSD-socket backend for constrained and embedded targets.<br/>• Pluggable allocator providers supporting both a hosted heap-managed model and an embedded no-heap arena model with preallocated per-context/request pools sized for N concurrent in-flight requests.<br/>• Three request-completion styles for every asynchronous operation: blocking await (sync), completion callback (async), and cooperative single-threaded polling via pubnub_process for no-thread event loops.<br/>• Request/future handles with a three-level timeout hierarchy (global, endpoint, per-request), configurable in-flight concurrency, and explicit bounded-queue backpressure.<br/>• Compile-time secure transport (PUBNUB_ENABLE_SECURE_TRANSPORT) with OpenSSL and mbedTLS TLS stacks selectable per transport backend; plaintext requires explicit opt-out.<br/>• Named build profiles (full, minimal, embedded) with per-profile memory and latency budgets, plus explicit CMake feature toggles for every feature module.<br/>• Payload crypto module with an AES-256-CBC cryptor using a random initialization vector (identifier ACRH) and a legacy cryptor, exposed through a pluggable crypto provider contract.<br/>• Publish API: synchronous and asynchronous delivery, GET and POST transport, store flag with per-message TTL, stream-filter metadata, raw JSON value trees, optional body compression, and file-message publishing.<br/>• Subscribe API (event-engine, PubSub v2): channels, channel groups, presence channels, wildcard subscriptions, stream-filter expressions, and timetoken cursor restore, with typed listeners for messages, signals, message actions, files, presence, and App Context objects.<br/>• Presence API: here-now, where-now, get/set presence state, and heartbeat.<br/>• Channel Groups API: add and remove channels, list channels in a group, and remove a group.<br/>• Message Persistence (Storage) API: fetch messages with metadata, message actions, file, message-type and publisher-UUID includes, reverse ordering, count and start/end bounds, delete messages, and message counts.<br/>• Message Actions API: add, get, and remove reactions on published messages.<br/>• Signal API: lightweight signal publishing.<br/>• Files API: send, list, download, delete, generate a file URL, and publish a file message.<br/>• App Context (Objects v2) API: get/set/remove UUID and channel metadata, list all UUID and channel metadata, and manage memberships and channel members.<br/>• Access Manager v3 API: grant, parse, set, and revoke resource tokens.<br/>• Mobile Push API: add, remove, and list channels for a device and remove a device, for the APNS2 and FCM gateways.<br/>• Time API: fetch the current PubNub network timetoken. |

1.0.0

September 21, 2026

Added

Ground-up rewrite of the PubNub C SDK: a platform-neutral C11 core (with a C99 compatibility mode) built around six pluggable provider families — transport, serialization, crypto, allocator, logger, and platform. Multi-context architecture with no static or global per-context state; multiple independent client contexts operate concurrently in a single process. Pluggable HTTP transport providers: a libcurl-backed backend for hosted platforms and a native BSD-socket backend for constrained and embedded targets. Pluggable allocator providers supporting both a hosted heap-managed model and an embedded no-heap arena model with preallocated per-context/request pools sized for N concurrent in-flight requests. Three request-completion styles for every asynchronous operation: blocking await (sync), completion callback (async), and cooperative single-threaded polling via pubnub_process for no-thread event loops. Request/future handles with a three-level timeout hierarchy (global, endpoint, per-request), configurable in-flight concurrency, and explicit bounded-queue backpressure. Compile-time secure transport (PUBNUB_ENABLE_SECURE_TRANSPORT) with OpenSSL and mbedTLS TLS stacks selectable per transport backend; plaintext requires explicit opt-out. Named build profiles (full, minimal, embedded) with per-profile memory and latency budgets, plus explicit CMake feature toggles for every feature module. Payload crypto module with an AES-256-CBC cryptor using a random initialization vector (identifier ACRH) and a legacy cryptor, exposed through a pluggable crypto provider contract. Publish API: synchronous and asynchronous delivery, GET and POST transport, store flag with per-message TTL, stream-filter metadata, raw JSON value trees, optional body compression, and file-message publishing. Subscribe API (event-engine, PubSub v2): channels, channel groups, presence channels, wildcard subscriptions, stream-filter expressions, and timetoken cursor restore, with typed listeners for messages, signals, message actions, files, presence, and App Context objects. Presence API: here-now, where-now, get/set presence state, and heartbeat. Channel Groups API: add and remove channels, list channels in a group, and remove a group. Message Persistence (Storage) API: fetch messages with metadata, message actions, file, message-type and publisher-UUID includes, reverse ordering, count and start/end bounds, delete messages, and message counts. Message Actions API: add, get, and remove reactions on published messages. Signal API: lightweight signal publishing. Files API: send, list, download, delete, generate a file URL, and publish a file message. App Context (Objects v2) API: get/set/remove UUID and channel metadata, list all UUID and channel metadata, and manage memberships and channel members. Access Manager v3 API: grant, parse, set, and revoke resource tokens. Mobile Push API: add, remove, and list channels for a device and remove a device, for the APNS2 and FCM gateways. Time API: fetch the current PubNub network timetoken.