C-Core (legacy) SDK 7.0.0 migration guide

New SDK available

C-Core (legacy) is still supported. If you are starting a new project, use the new C SDK.

This guide summarizes the differences between 6.X.X versions and 7.0.0 and shows how to migrate to C-Core SDK 7.0.0.

C-Core (legacy) SDK version 7.0.0 makes DNS server configuration per-context, replaces the logging subsystem with an advanced pluggable logger architecture, and adds logging methods to the C++ wrapper class. This applies to all C-Core (legacy) SDK flavors: C-Core (legacy), POSIX C, POSIX C++, Windows C, Windows C++, FreeRTOS, and Mbed.

Earlier migration guides

If you are upgrading from a version before 6.0.0, read the C-Core SDK 6.0.0 migration guide first.

What has changed

See the major differences between versions:

Feature	C-Core SDK 6.X.X	C-Core SDK 7.0.0
DNS server functions	Global (no context parameter)	Per-context (`pubnub_t* pb` added as first parameter)
Logging header	`#include "core/pubnub_log.h"`	`#include "core/pubnub_logger.h"`
Logging functions	`PUBNUB_LOG_PRINTF(...)` macros	`pubnub_log_text()`, `pubnub_log_text_formatted()`, `pubnub_log_object()`, `pubnub_log_error()`
Log level enum	Sequential: `NONE=0, ERROR=1, ... TRACE=5`	Bitmask: `TRACE=1, DEBUG=2, INFO=4, WARNING=8, ERROR=16, NONE=32`
Compile-time level macro	`PUBNUB_LOG_LEVEL`	`PUBNUB_LOG_MIN_LEVEL`
Custom output / runtime callback	Override `PUBNUB_LOG_PRINTF` macro or `pubnub_set_log_callback(fn)`	Register custom `pubnub_logger_t` with `pubnub_logger_add(pb, logger)`
WATCH_* macros	`WATCH_INT(x)`, `WATCH_STR(x)`, etc.	Removed. Use structured logging (`pubnub_log_object`)
C++ wrapper (POSIX C++, Windows C++)	No logging methods	New methods: `logger_add`, `logger_remove`, `set_log_level`, `log_text`, `log_object`, `log_error`
Feature flags	Always compiled in	`PUBNUB_USE_LOGGER`, `PUBNUB_USE_DEFAULT_LOGGER`

Breaking changes

Change	Platforms affected
DNS server API	All (C-Core (legacy), POSIX C, POSIX C++, Windows C, Windows C++, FreeRTOS, Mbed)
Logging subsystem	All
Log level changes	All
Build configuration	All
C++ wrapper	POSIX C++, Windows C++
Platform-specific default loggers	POSIX C, POSIX C++, Windows C, Windows C++, FreeRTOS, Microchip Harmony

DNS server API

Applies to: All platforms

Starting with 7.0.0, all 14 DNS server functions in core/pubnub_dns_servers.h require a pubnub_t* context as their first parameter. Previously, these functions operated on global state. Now DNS server configuration is per-context.

This change affects all functions guarded by PUBNUB_SET_DNS_SERVERS.

IPv4 functions

Function	C-Core SDK 6.X.X	C-Core SDK 7.0.0
`pubnub_dns_set_primary_server_ipv4`	`(struct pubnub_ipv4_address ipv4)`	`(pubnub_t* pb, struct pubnub_ipv4_address ipv4)`
`pubnub_dns_set_secondary_server_ipv4`	`(struct pubnub_ipv4_address ipv4)`	`(pubnub_t* pb, struct pubnub_ipv4_address ipv4)`
`pubnub_dns_set_primary_server_ipv4_str`	`(char const* ipv4_str)`	`(pubnub_t* pb, char const* ipv4_str)`
`pubnub_dns_set_secondary_server_ipv4_str`	`(char const* ipv4_str)`	`(pubnub_t* pb, char const* ipv4_str)`
`pubnub_get_dns_primary_server_ipv4`	`(struct pubnub_ipv4_address* o_ipv4)`	`(pubnub_t* pb, struct pubnub_ipv4_address* o_ipv4)`
`pubnub_get_dns_secondary_server_ipv4`	`(struct pubnub_ipv4_address* o_ipv4)`	`(pubnub_t* pb, struct pubnub_ipv4_address* o_ipv4)`
`pubnub_dns_read_system_servers_ipv4`	`(struct pubnub_ipv4_address* o_ipv4, size_t n)`	`(pubnub_t* pb, struct pubnub_ipv4_address* o_ipv4, size_t n)`

IPv6 functions (require `PUBNUB_USE_IPV6`)

Function	C-Core SDK 6.X.X	C-Core SDK 7.0.0
`pubnub_dns_set_primary_server_ipv6`	`(struct pubnub_ipv6_address ipv6)`	`(pubnub_t* pb, struct pubnub_ipv6_address ipv6)`
`pubnub_dns_set_secondary_server_ipv6`	`(struct pubnub_ipv6_address ipv6)`	`(pubnub_t* pb, struct pubnub_ipv6_address ipv6)`
`pubnub_dns_set_primary_server_ipv6_str`	`(char const* ipv6_str)`	`(pubnub_t* pb, char const* ipv6_str)`
`pubnub_dns_set_secondary_server_ipv6_str`	`(char const* ipv6_str)`	`(pubnub_t* pb, char const* ipv6_str)`
`pubnub_get_dns_primary_server_ipv6`	`(struct pubnub_ipv6_address* o_ipv6)`	`(pubnub_t* pb, struct pubnub_ipv6_address* o_ipv6)`
`pubnub_get_dns_secondary_server_ipv6`	`(struct pubnub_ipv6_address* o_ipv6)`	`(pubnub_t* pb, struct pubnub_ipv6_address* o_ipv6)`
`pubnub_dns_read_system_servers_ipv6`	N/A (new in 6.2.0)	`(pubnub_t* pb, struct pubnub_ipv6_address* o_ipv6, size_t n)`

Fallback macros

The fallback macros (when PUBNUB_SET_DNS_SERVERS is disabled) also gained the pb parameter, so code using the macro forms also needs updating.

Before (6.X.X)
After (7.0.0)

#include "core/pubnub_dns_servers.h"


/* DNS servers were global — no context needed */
struct pubnub_ipv4_address dns = {{8, 8, 8, 8}};
pubnub_dns_set_primary_server_ipv4(dns);
pubnub_dns_set_secondary_server_ipv4_str("8.8.4.4");


/* Read system DNS servers */
struct pubnub_ipv4_address servers[4];
int count = pubnub_dns_read_system_servers_ipv4(servers, 4);

#include "core/pubnub_dns_servers.h"


/* DNS servers are now per-context — pass pubnub_t* as first argument */
pubnub_t* pb = pubnub_alloc();
pubnub_init(pb, "pub-key", "sub-key");


struct pubnub_ipv4_address dns = {{8, 8, 8, 8}};
pubnub_dns_set_primary_server_ipv4(pb, dns);
pubnub_dns_set_secondary_server_ipv4_str(pb, "8.8.4.4");


/* Read system DNS servers — also requires context now */
struct pubnub_ipv4_address servers[4];
int count = pubnub_dns_read_system_servers_ipv4(pb, servers, 4);


/* IPv6 system DNS discovery (new in 6.2.0, requires PUBNUB_USE_IPV6) */
struct pubnub_ipv6_address servers6[4];
int count6 = pubnub_dns_read_system_servers_ipv6(pb, servers6, 4);
show all 17 lines

Logging subsystem

Applies to: All platforms

Starting with 7.0.0, the SDK replaces its legacy logging subsystem (core/pubnub_log.h) with a new advanced logging system (core/pubnub_logger.h). The new system introduces per-context logging, multiple simultaneous logger support, structured data logging, network request/response logging, and runtime log level control.

The files core/pubnub_log.h and core/pubnub_log.c are deleted. Any direct references to them cause compilation errors.

Removed APIs

The following are deleted and cause compilation errors if referenced:

Removed API	Replacement
`#include "core/pubnub_log.h"`	`#include "core/pubnub_logger.h"`
`PUBNUB_LOG_PRINTF(...)`	`pubnub_log_text_formatted(pb, level, location, format, ...)`
`PUBNUB_LOG_ERROR(...)`, `PUBNUB_LOG_WARNING(...)`, `PUBNUB_LOG_INFO(...)`, `PUBNUB_LOG_DEBUG(...)`, `PUBNUB_LOG_TRACE(...)`	`pubnub_log_text_formatted(pb, level, location, format, ...)`
`WATCH_INT(x)`, `WATCH_STR(x)`, `WATCH_ENUM(x)`, `WATCH_ULONG(x)`	`pubnub_log_object(pb, level, location, value, details)`
`pubnub_set_log_callback(fn)` / `PUBNUB_USE_LOG_CALLBACK`	Create a custom `pubnub_logger_t` and register with `pubnub_logger_add(pb, logger)`. `PUBNUB_USE_LOGGER` controls whether the logging subsystem is compiled in.
`PUBNUB_LOG_LEVEL` (compile-time macro)	`PUBNUB_LOG_MIN_LEVEL`

New logging public API

All functions are part of the public C API in core/pubnub_logger.h.

Logger lifecycle

Function	Description
`pubnub_logger_alloc(vtable, user_data)`	Create a custom logger with a vtable and optional user data. Returns `NULL` on failure.
`pubnub_logger_user_data(logger)`	Retrieve user data associated with a custom logger.
`pubnub_logger_free(logger)`	Free a custom logger. Calls the logger's `destroy()` callback if provided. Sets `*logger` to `NULL`.

Logger registration

Function	Description
`pubnub_logger_add(pb, logger)`	Register a custom logger with a PubNub context. Multiple loggers can be registered. Returns `0` on success.
`pubnub_logger_remove(pb, logger)`	Unregister a custom logger. Caller must still call `pubnub_logger_free()`. Returns `0` on success.
`pubnub_logger_remove_all(pb)`	Unregister all custom loggers. Caller must free each logger individually.

Log level control

Function	Description
`pubnub_logger_set_log_level(pb, level)`	Set the minimum log level. Messages below this level are not dispatched.
`pubnub_logger_log_level(pb)`	Get the current minimum log level. Default: `PUBNUB_LOG_LEVEL_DEBUG`.

Logging functions

Function	Description
`pubnub_log_text(pb, level, location, message)`	Log a plain text message.
`pubnub_log_text_formatted(pb, level, location, format, ...)`	Log a formatted text message (printf-style).
`pubnub_log_object(pb, level, location, value, details)`	Log a structured object/data.
`pubnub_log_error(pb, location, error_code, error_message, details)`	Log an error. Level is always `PUBNUB_LOG_LEVEL_ERROR`.

Replace logging macros

Before (6.X.X)
After (7.0.0)

#include "core/pubnub_log.h"


PUBNUB_LOG_ERROR("Failed to publish: %d", result);
PUBNUB_LOG_DEBUG("Channel: %s", channel);

#include "core/pubnub_logger.h"


pubnub_log_text_formatted(pb, PUBNUB_LOG_LEVEL_ERROR, "app.c:42",
                          "Failed to publish: %d", result);
pubnub_log_text_formatted(pb, PUBNUB_LOG_LEVEL_DEBUG, "app.c:50",
                          "Channel: %s", channel);


/* Or use pubnub_log_text() for non-formatted messages */
pubnub_log_text(pb, PUBNUB_LOG_LEVEL_INFO, "app.c:60",
                "Subscription connected");

Replace `PUBNUB_LOG_PRINTF` override

Before (6.X.X)
After (7.0.0)

/* Compile-time macro override */
#define PUBNUB_LOG_PRINTF(...) my_log_func(__VA_ARGS__)

#include "core/pubnub_logger.h"


/* Runtime custom logger registration */
static void my_logger_handler(const pubnub_logger_t*      logger,
                               const pubnub_log_message_t* message) {
    if (message->message_type == PUBNUB_LOG_MESSAGE_TYPE_TEXT) {
        const pubnub_log_message_text_t* text =
            (const pubnub_log_message_text_t*)message;
        my_log_func("[%s] %s\n", message->pubnub_id, text->message);
    }
}


static const struct pubnub_logger_interface my_vtable = {
    .trace   = my_logger_handler,
    .debug   = my_logger_handler,
    .info    = my_logger_handler,
    .warn    = my_logger_handler,
    .error   = my_logger_handler,
    .destroy = NULL,
};


/* Register after creating context */
pubnub_logger_t* my_logger = pubnub_logger_alloc(&my_vtable, NULL);
pubnub_logger_add(pb, my_logger);
show all 24 lines

Replace `pubnub_set_log_callback`

Before (6.X.X)
After (7.0.0)

void my_callback(enum pubnub_log_level level, const char* message) {
    fprintf(log_file, "[%d] %s", level, message);
}
pubnub_set_log_callback(my_callback);

#include "core/pubnub_logger.h"


typedef struct {
    FILE* file;
} my_context;


static void my_handler(const pubnub_logger_t*      logger,
                        const pubnub_log_message_t* message) {
    my_context* ctx = (my_context*)pubnub_logger_user_data(
        (pubnub_logger_t*)logger);
    if (message->message_type == PUBNUB_LOG_MESSAGE_TYPE_TEXT) {
        const pubnub_log_message_text_t* text =
            (const pubnub_log_message_text_t*)message;
        fprintf(ctx->file, "[%s] %s\n", message->pubnub_id, text->message);
    }
}


static void my_destroy(pubnub_logger_t* logger) {
    my_context* ctx = (my_context*)pubnub_logger_user_data(logger);
    if (ctx->file) fclose(ctx->file);
    free(ctx);
}


static const struct pubnub_logger_interface file_vtable = {
    .trace = my_handler, .debug = my_handler, .info = my_handler,
    .warn = my_handler, .error = my_handler, .destroy = my_destroy,
};


/* Setup */
my_context* ctx = malloc(sizeof(*ctx));
ctx->file = fopen("pubnub.log", "a");
pubnub_logger_t* file_logger = pubnub_logger_alloc(&file_vtable, ctx);
pubnub_logger_add(pb, file_logger);
show all 33 lines

Replace `WATCH_*` macros

Before (6.X.X)
After (7.0.0)

WATCH_INT(result);
WATCH_STR(channel);

#include "core/pubnub_log_value.h"


pubnub_log_value_t params = pubnub_log_value_map_init();
PUBNUB_LOG_MAP_SET_NUMBER(&params, result)
PUBNUB_LOG_MAP_SET_STRING(&params, channel)
pubnub_log_object(pb, PUBNUB_LOG_LEVEL_DEBUG, "app.c:42",
                  &params, "debug values");

Structured logging scope

All pubnub_log_value_t structures and their string pointers live on the stack. All values, containers, and the log call must be in the same scope. If a value goes out of scope before the logging function reads it, you get undefined behavior.

Log level changes

Applies to: All platforms

The log level enum changed from sequential integers with reversed ordering to bitmask powers of 2 with natural ordering.

Before (6.X.X)
After (7.0.0)

/* Sequential integers, REVERSED ordering (NONE is lowest) */
enum pubnub_log_level {
    PUBNUB_LOG_LEVEL_NONE    = 0,   /* Logging disabled */
    PUBNUB_LOG_LEVEL_ERROR   = 1,
    PUBNUB_LOG_LEVEL_WARNING = 2,
    PUBNUB_LOG_LEVEL_INFO    = 3,
    PUBNUB_LOG_LEVEL_DEBUG   = 4,
    PUBNUB_LOG_LEVEL_TRACE   = 5    /* Most verbose */
};
/* Filter: if (level <= PUBNUB_LOG_LEVEL) → emit */

/* Bitmask powers of 2, NATURAL ordering (TRACE is lowest) */
enum pubnub_log_level {
    PUBNUB_LOG_LEVEL_TRACE   = (1 << 0),  /*  1 — Most verbose */
    PUBNUB_LOG_LEVEL_DEBUG   = (1 << 1),  /*  2 */
    PUBNUB_LOG_LEVEL_INFO    = (1 << 2),  /*  4 */
    PUBNUB_LOG_LEVEL_WARNING = (1 << 3),  /*  8 */
    PUBNUB_LOG_LEVEL_ERROR   = (1 << 4),  /* 16 */
    PUBNUB_LOG_LEVEL_NONE    = (1 << 5),  /* 32 — Logging disabled */
};
/* Filter: if (level >= minimum_level) → emit */

Comparison direction changed

If your code compares log level values numerically (for example, if (level <= PUBNUB_LOG_LEVEL_INFO)), the comparison direction has changed. In the old system NONE < ERROR < TRACE. In the new system TRACE < DEBUG < INFO < WARNING < ERROR < NONE.

Build configuration

Applies to: All platforms

Compile-time log level stripping

The compile-time macro for log level filtering has changed.

Before (6.X.X)
After (7.0.0)

# Old build flag
-DPUBNUB_LOG_LEVEL=PUBNUB_LOG_LEVEL_WARNING

# New build flag — uses short level names
-DPUBNUB_LOG_MIN_LEVEL=WARNING


# Other examples:
-DPUBNUB_LOG_MIN_LEVEL=TRACE    # Maximum verbosity
-DPUBNUB_LOG_MIN_LEVEL=DEBUG    # Default
-DPUBNUB_LOG_MIN_LEVEL=NONE     # Disable all logging at compile time

C++ wrapper

Applies to: POSIX C++, Windows C++

New methods are added to the pubnub::context class in cpp/pubnub_common.hpp, guarded by #if PUBNUB_USE_LOGGER. These delegate directly to the C public API functions.

Method	Description
`logger_add(pubnub_logger_t* logger)`	Register a custom logger. Returns `0` on success.
`logger_remove(pubnub_logger_t* logger)`	Unregister a custom logger. Returns `0` on success.
`logger_remove_all()`	Unregister all custom loggers.
`set_log_level(pubnub_log_level level)`	Set minimum log level for this context.
`log_level()`	Get current minimum log level. Default: `PUBNUB_LOG_LEVEL_DEBUG`.
`log_text(pubnub_log_level level, char const* location, char const* message)`	Log a plain text message.
`log_text(pubnub_log_level level, char const* location, std::string const& message)`	Log a text message from `std::string`.
`log_object(pubnub_log_level level, char const* location, pubnub_log_value_t const* message, char const* details)`	Log a structured object with optional details.
`log_error(char const* location, int error_code, char const* error_message, char const* details)`	Log an error (always `PUBNUB_LOG_LEVEL_ERROR`).

Basic C++ logging

#include "pubnub_common.hpp"

pubnub::context ctx("demo", "demo");

/* Log simple text messages */
ctx.log_text(PUBNUB_LOG_LEVEL_INFO,
             "main.cpp:10",
             "PubNub context initialized");

/* Log with std::string */
std::string msg = "Subscribing to channel: " + channel_name;
ctx.log_text(PUBNUB_LOG_LEVEL_DEBUG, "main.cpp:15", msg);

/* Log an error */
ctx.log_error("main.cpp:25", -1, "Connection failed", "Timeout after 30s");

Custom logger in C++

#include "pubnub_common.hpp"
#include "core/pubnub_logger.h"


static void my_info_handler(const pubnub_logger_t*      logger,
                             const pubnub_log_message_t* message) {
    if (message->message_type == PUBNUB_LOG_MESSAGE_TYPE_TEXT) {
        const pubnub_log_message_text_t* text =
            (const pubnub_log_message_text_t*)message;
        std::cout << "[INFO] " << text->message << std::endl;
    }
}


static const struct pubnub_logger_interface my_vtable = {
    .trace   = NULL,
    .debug   = NULL,
    .info    = my_info_handler,
    .warn    = NULL,
    .error   = NULL,
    .destroy = NULL,
};


int main() {
    pubnub::context ctx("demo", "demo");


    /* Create and register custom logger */
    pubnub_logger_t* logger = pubnub_logger_alloc(&my_vtable, NULL);
    ctx.logger_add(logger);


    /* Set minimum level to INFO (skip TRACE and DEBUG) */
    ctx.set_log_level(PUBNUB_LOG_LEVEL_INFO);


    /* ... use PubNub ... */


    /* Cleanup */
    ctx.logger_remove(logger);
    pubnub_logger_free(&logger);
}
show all 37 lines

Feature flags

Two new macros control the logging subsystem. Both are defined in each platform's pubnub_config.h and default to 1 (enabled).

Macro	Default	Description
`PUBNUB_USE_LOGGER`	`1`	Enable/disable the entire logging subsystem. When `0`, all logging macros become no-ops and logger API functions are not compiled.
`PUBNUB_USE_DEFAULT_LOGGER`	`1`	Enable/disable the built-in default platform logger. When `0`, no logger is registered automatically — you must register your own via `pubnub_logger_add()`.

New source files

If you maintain custom build scripts or Makefiles, add the following files.

Always required when `PUBNUB_USE_LOGGER=1`

File	Purpose
`core/pubnub_logger.c`	Public logger API implementation
`core/pbcc_logger_manager.c`	Logger manager (dispatches to registered loggers)
`core/pubnub_log_value.c`	Structured log value types

Required only when `PUBNUB_USE_DEFAULT_LOGGER=1`

Add exactly one platform-specific default logger:

Platform	File
POSIX / Windows	`core/pubnub_stdio_logger.c`
FreeRTOS	`freertos/pubnub_freertos_logger.c`
Microchip Harmony	`microchip_harmony/pubnub_harmony_logger.c`

Platform-specific default loggers

Applies to: All platforms (each platform uses its own logger implementation)

When PUBNUB_USE_DEFAULT_LOGGER is 1 (default), each new PubNub context automatically registers a platform-appropriate logger.

Platform	File	Output	Timestamps
POSIX / Windows	`core/pubnub_stdio_logger.c`	`fprintf(stdout)` for TRACE/DEBUG/INFO/WARN; `fprintf(stderr)` for ERROR	ISO 8601 with milliseconds
FreeRTOS	`freertos/pubnub_freertos_logger.c`	`printf()` for all levels	ISO 8601 when wall-clock available; `xTaskGetTickCount()` tick-based fallback
Microchip Harmony	`microchip_harmony/pubnub_harmony_logger.c`	`SYS_CONSOLE_PRINT()` for all levels	Raw Unix timestamp; `SYS_TMR_TickCountGet()` fallback

Output format example (POSIX/Windows)

2026-03-03T10:11:31.456Z PubNub-a1b2c3d4 DEBUG core/pubnub_coreapi.c:123 Publishing to channel 'my-channel'

Migration steps

To migrate to C-Core SDK 7.0.0:

Update DNS server function calls. Add pubnub_t* context as the first argument to all DNS server functions:

Action	Description
Add `pb` as the first argument to all `pubnub_dns_set_`, `pubnub_get_dns_`, and `pubnub_dns_read_system_servers_*` calls	All 14 DNS functions (7 IPv4 + 7 IPv6) now require a `pubnub_t*` context. This also applies to fallback macros when `PUBNUB_SET_DNS_SERVERS` is disabled.

Update logging includes:

Action	Description
Replace `#include "core/pubnub_log.h"` with `#include "core/pubnub_logger.h"`	The old header file is deleted. For structured log values and convenience macros, also include `core/pubnub_log_value.h`.

Replace old logging macros with public API functions:

Action	Description
Replace `PUBNUB_LOG_ERROR(...)`, `PUBNUB_LOG_WARNING(...)`, etc. with `pubnub_log_text_formatted()`	The new function requires a `pubnub_t*` context, a log level, a location string, and a format string with arguments.
Replace `pubnub_log_text()` for non-formatted messages	Use when you don't need printf-style formatting.

Replace PUBNUB_LOG_PRINTF override with runtime custom logger registration:

Action Description
Remove #define PUBNUB_LOG_PRINTF(...) overrides Create a pubnub_logger_interface vtable and register a custom logger at runtime using pubnub_logger_alloc() and pubnub_logger_add().

Action	Description
Remove `#define PUBNUB_LOG_PRINTF(...)` overrides	Create a `pubnub_logger_interface` vtable and register a custom logger at runtime using `pubnub_logger_alloc()` and `pubnub_logger_add()`.

Replace pubnub_set_log_callback with custom logger:

Action	Description
Remove `pubnub_set_log_callback()` calls	Create a custom logger with a vtable and register it with `pubnub_logger_add()`. Use `pubnub_logger_user_data()` to access custom state from within callbacks.

Replace WATCH_* macros with structured logging:

Action	Description
Replace `WATCH_INT(x)`, `WATCH_STR(x)`, etc.	Use `pubnub_log_value_t` types and `pubnub_log_object()`. Convenience macros like `PUBNUB_LOG_MAP_SET_NUMBER` and `PUBNUB_LOG_MAP_SET_STRING` are available in `core/pubnub_log_value.h`.

Update compile-time level configuration:

Action Description
Replace -DPUBNUB_LOG_LEVEL=PUBNUB_LOG_LEVEL_WARNING with -DPUBNUB_LOG_MIN_LEVEL=WARNING The new macro uses short level names: TRACE, DEBUG, INFO, WARNING, ERROR, NONE.

Action	Description
Replace `-DPUBNUB_LOG_LEVEL=PUBNUB_LOG_LEVEL_WARNING` with `-DPUBNUB_LOG_MIN_LEVEL=WARNING`	The new macro uses short level names: `TRACE`, `DEBUG`, `INFO`, `WARNING`, `ERROR`, `NONE`.

Update runtime level filtering:

Action	Description
Use `pubnub_logger_set_log_level(pb, level)` to control runtime filtering	The old system only supported compile-time filtering. The new system supports both compile-time stripping and runtime filtering per context.

(C++ only) Use new context methods for logging:

Action	Description
Use `ctx.logger_add()`, `ctx.set_log_level()`, `ctx.log_text()`, etc.	The `pubnub::context` class in `pubnub_common.hpp` provides C++ wrappers for all logging API functions. No include changes needed — `core/pubnub_logger.h` is automatically included when `PUBNUB_USE_LOGGER` is enabled.

Update build scripts. Add new source files if you maintain custom build scripts:

Action	Description
Add `core/pubnub_logger.c`, `core/pbcc_logger_manager.c`, `core/pubnub_log_value.c`	Always required when `PUBNUB_USE_LOGGER=1` (default).
Add exactly one platform-specific default logger file	Required when `PUBNUB_USE_DEFAULT_LOGGER=1` (default). See New source files for platform-specific file names.

Clean up custom loggers before freeing the PubNub context:

Action	Description
Call `pubnub_logger_remove(pb, logger)` and `pubnub_logger_free(&logger)` before `pubnub_free(pb)`	Custom loggers must be unregistered and freed before the context is freed. `pubnub_logger_free()` calls the logger's `destroy()` callback if provided.

Test your application. Pay special attention to DNS configuration, logging output, and any custom logging integrations.

Additional resources

For API details, see the C-Core (legacy) SDK documentation. For the full logging reference, see Logging. For questions or issues, contact PubNub support.

New SDK available

Earlier migration guides

What has changed​

Breaking changes​

DNS server API​

IPv4 functions​

IPv6 functions (require PUBNUB_USE_IPV6)​

Fallback macros

Logging subsystem​

Removed APIs​

New logging public API​

Logger lifecycle​

Logger registration​

Log level control​

Logging functions​

Replace logging macros​

Replace PUBNUB_LOG_PRINTF override​

Replace pubnub_set_log_callback​

Replace WATCH_* macros​

Structured logging scope

Log level changes​

Comparison direction changed

Build configuration​

Compile-time log level stripping​

C++ wrapper​

Basic C++ logging​

Custom logger in C++​

Feature flags​

New source files​

Always required when PUBNUB_USE_LOGGER=1​

Required only when PUBNUB_USE_DEFAULT_LOGGER=1​

Platform-specific default loggers​

Output format example (POSIX/Windows)​

Migration steps​

Additional resources​

What has changed

Breaking changes

DNS server API

IPv4 functions

IPv6 functions (require `PUBNUB_USE_IPV6`)

Logging subsystem

Removed APIs

New logging public API

Logger lifecycle

Logger registration

Log level control

Logging functions

Replace logging macros

Replace `PUBNUB_LOG_PRINTF` override

Replace `pubnub_set_log_callback`

Replace `WATCH_*` macros

Log level changes

Build configuration

Compile-time log level stripping

C++ wrapper

Basic C++ logging

Custom logger in C++

Feature flags

New source files

Always required when `PUBNUB_USE_LOGGER=1`

Required only when `PUBNUB_USE_DEFAULT_LOGGER=1`

Platform-specific default loggers

Output format example (POSIX/Windows)

Migration steps

Additional resources