Changes to version 2.4.0
------------------------

- Added function CS104_Connection_isConnected
- TLS integration code for mbedtls 2.28 and 3.6 updated for better compliance with IEC 62351 security event requirements
- TLS (mbedtls 3.6): explicitely disabled hostname verfication to avoid problem with mbedtls 3.6.3 and later
- updated minimum required cmake version to be compatible with cmake 4.0
- added integration code for secure authentication (IEC 60870-5-7:2013) module (the actual secure authentication code is available as commercial add-on)
- CS104 slave: added functions to set callback handlers for reset process and delay acquisition commands (#137)
- CS101/CS104 slave: only allow known CAA for internally handled commands -> added callback CS101_IsCAAllowedHandler (LIB8705-126)
- CS101/CS104 slave: reject commands with broadcast CA when not allowed for command type (LIB8705-130)
- CS104 slave: fixed potentical deadlock - lowPrioQueue doesn't have to be locked during sendASDU call
- CS104 slave: fixed detection of unconfirmed messages when connection is closed
- CS104 client: added threadless operation mode (CS104_Connection_startThreadless/stopThreadless/run) and example cs104_client_no_threads (LIB8705-134)
- CS104 client: implemented T1 timeout when waiting for STARTDT/STOPDT confirmation messages
- Added IMasterConnection_sendASDUEx to allow bypassing queues for correct message ordering in GI responses (LIB8705-149)
- updated CS 104 server example to show standard compliant interrogation handling
- fix: CS104 client is sending same S message multiple times when sending STOPDT_ACT (LIB8705-150)
- fix: slave is sending STOP-DT CON when there are unconfirmed sent I messages from the high prio queue (LIB8705-148)
- added some warning/alarms to mbedtls 2.28 integration to comply with IEC 62351-100-3 test cases
- CS101/CS104 slave: added additional options for interrogation handling to allow better compliance with priority rules


Changes to version 2.3.6
------------------------

- fixed wrong size calculation when decoding FileDirectory(F_DR_TA_1) type (#179)
- CS104 Slave/CS101 Slave: fixed handling of test commands to be compliant with conformance test case (LIB8705-128)
- CS104_Connection: fixed possible application crash when application is trying to send a message after connection is closed (LIB8705-127)
- fixed all unchecked results from calls to CS101_ASDU_getElement/CS101_ASDU_getElementEx (#178) -> fixes vulnerability GHSA-75pr-rr3v-j6px (possible NULL pointer dereference when invalid test command is received by CS 104 server)
- code format updates


Changes to version 2.3.5
------------------------

- fixed MessageQueue_isAsduAvailable to solve CPU usage problem in CS104 server (LIB8705-123)
- fixed problem in normalized value handling (LIB8705-122)

Changes to version 2.3.4
------------------------

- removed internal calls to CS101_ASDU_createFromBuffer to avoid dynamic memory allocation while handling received ASDUs
- added CS101_ASDU_createFromBuffer to API
- added ability to change config defines from make command (#169)
- Time(Linux): always use clock_gettime; cleanup cmake files to remove checks for clock_gettime (#162)
- Time(windows): fixed - Hal_getMonotonicTimeInMs() doesn't call GetTickCount64 correctly (#163)

Changes to version 2.3.3
------------------------

- TLS: support for TLS 1.3 (when using mbedtls 3.6)
- TLS: support to select TLS cipher suites 
- CS104 slave: check IOA of received commands where IOA is fixed to 0 (LIB8705-101)
- CS 104 slave: only send S message after receiving STOPDT-ACT when there are unconfirmed outstanding I messages to be compliant with test case IEC 60870-5-604:2016-5.3.2.70 (LIB8705-97)
- fixed bug in test pattern for TestCommand (I651CL-25)
- fixed initialization problem in StepCommand_create (I651CL-22)
- disable support for C_TS_NA_1 for CS104 by default
- use monotonic time for timers when supported by platform (LIB8705-87)
- CS101 slave: updated behavior in unbalanced mode when FCB bit did not change (LIB8705-104)
- fixed - k parameter from user configuration is not used
- added handling of pending unconfirmed stopped state (LIB8705-83)
- CS104_Connection: call connection handler only outside of connection lock to avoid deadlocks in user code (LIB8705-62)
- CS104 connection: fixed potential race condition when connection is closed by peer (#147)
- CS104 slave: fixed - lock not released in error case (#138)
- fixed - CS 104 server: invalid read - when MasterConnection_deactivate is called after MasterConnection_deinit (LIB8705-54)
- fixed - CS 104 server: connection is closed by server when receiving S message in inactive state (LIB8705-55)
- fixed - CS104_Connection deadlock when sending commands/ASDUs (#134)(LIB8705-52)


Changes to version 2.3.2
------------------------

- TLS support now requires mbedtls 2.28
- updated HAL layer
- Added new IEC 62351-3 related TLS features (session resumption, alarms, ...)
- CS101 balanced link layer: Send request-status-of-link before calling reset-of-remote-link
- CS101 unbalanced master: Send request-status-of-link before calling reset-of-remote-link, added delay before repeating request-status-of-link
- added function CS101_ASDU_clone
- fixed - TLS: configured CRL are ignored (#117)
- integrated code to serve files
- other small bug fixes and improvements
- CS104 client: added connection event when connect failed


Changes to version 2.3.1
------------------------

- TLS support now requires mbedtls 2.16.12
- CS104 client/master: add support to specify local interface/IP address
- Macos HAL layer: replaced semaphores by mutex
- updated HAL layer
- fix - Possible buffer overflow when formatting IPv6 addresses (#96)
- fixed - write to queueEntry is not protected (#99)
- fixed bug in CS101_ASDU_setNumberOfElements (#91)
- CS104 slave: fixed problem in TEST-FR con timeout handling
- CS101 master: fixed problem not sending broadcast messages (#88)
- CS101 slave: fixed potential crash when application layer parameters don't match
- CS104 server: fixed - receiving I or S frame while in STOPDT should close connection


Changes to version 2.3.0
------------------------
- CS104 slave: send time sync response only to requesting client (#87)
- fixed a bug in StatusAndStatusChangeDetection type decoding
- fixed problem in TLS integration layer
- fixed wrong type in return value of TestCommandWithCP56Time2a_getCounter
- CS104 slave: close all open connections when server is stopped in non-treaded mode
- added QueryLog (F_SC_NB_1) information object type
- CS 101 slave: release plugin list in destroy function (#80)
- CS104 client: Added function CS104_Connection_sendTestCommandWithTimestamp to send C_TS_TA_1 test command
- CS104 slave: added support to handle test command C_TS_TA_1
- added missing value for IEC60870_QCC_FRZ_COUNTER_RESET (#78)
- CS104 slave: remove message from queue when confirmation received (see #77)
- CS104 master: confirm all received I messages before sending STOPDT ACT or closing the connection
- CS 104 slave: fixed bugs when TLS connection initilization fails (#75)
- fixed potential memory leak in CS104_Connection_connectAsync
- fixed wrong argument type of StepCommandWithCP56Time2a_destroy (#74)
- single point and double point information objects ignore invalid quality flags (#72)

Changes to version 2.2.1
------------------------
- CS104 slave: fixed problems in queue handling (#67)
- added missing return statement in CS101_ASDU_addPayload(#68)
- CS101_ASDU_addInformationObject now checks for correct object type
- windows socket driver: fixed - fail to detect peer close when read from socket
- fixed bug in BitString32 encoding (see #65)
- fixed - null pointer access when calling CS104_Slave_destroy without server running before (issue #64)
- added Bitstring32X_createEx functions to keep API backward compatible and allow setting of quality (issue #63)

Changes to version 2.2.0
------------------------
- CS 101/104 slave: improved stability when receiving corrupted messages
- CS 101/104 slave: added plugin interface
- CS101 master: fixed setting of own address in balanced mode (#51)
- CS101 slave: fixed bug in queue size initialization
- Socket HAL (linux/bsd): set default backlog to 2 (see #50)
- Socket HAL (linux/bsd): Socket_read detects closed socket
- fixed bugs in file handling messages
- fixed bug in OA decoding
- add support to create and handle private or not supported ASDU types
- CS104 master/slave: improved socket handling
- CS104 slave: improved memory handling and memory consumption
- removed CONFIG_CS104_SLAVE_POOL (and related) configuration option


Changes to version 2.1.1
------------------------
- CS 104 slave: added functions IMasterConnection_getPeerAddress and IMasterConnection_close
- CS 101/CS 104 slave: set P/N=1 (negative) when sending COT=44 or COT=45
- improved compatibility with VxWorks
- CS 104 slave: fixed bug in counter interrogation command handling - free stack allocated memory
- fixed some include file problems


Changes to version 2.1.0
------------------------
- CS104 slave: added support for multiple redundancy groups
- added non-threaded moded for CS 104 slave
- separated thread and semaphore support for CS 104 slave
- CS101 unbalanced link layer (master): automatically send request UD 1 when ACD bit is set in received frame
- added CS101_ASDU_getElementEx function to avoid dynamic memory allocation
- added support for static ASDU object allocation
- fixed length check when parsing M_EP_TD_1
- CS101 unbalanced master: fixed state machine problem with multiple slaves (some responses don't change state and master keeps locked on the slave)
- optionally compile library without HAL to simply using together with libiec61850


Changes to version 2.0.2
------------------------
- CS104 slave: added new CS104_ConnectionEventHandler to track connection events
- CS104 master/slave: added callback handlers to log raw messages
- CS101 master/slave: added callback handlers to log raw messages


Changes to version 2.0.1
------------------------
- fixed problems to compile code with C++
- CS101: added functions to better control link layer addresses
- CS101 master: added function to modify default link layer parameters
- link layer: fixed problem in test function handling
- application layer: allow configuration of maximum size of ASDU
- CS104 master: added new function CS104_Master_sendProcessCommandEx
- CS104: fixed timeout T2 problem
- and other small fixes


Changes to version 2.0.0
------------------------
- added support for CS 101 balanced and unbalanced serial link layer
- added serial port abstraction layer and implementations for linux and windows
- seperated lib60870-C and lib60870.NET into separate projects. Removed all .NET code from the lib60870 main branch
- added TLS support for CS 104
- API redesign. Not compatible with old API.
- updated and extended user guide
- added doxygen based API reference documentation
- added more examples

Changes to version 0.9.5
------------------------
- lib60870.NET: add support for server allowing multiple clients using the application layer (ServerMode.CONNECTION_IS_REDUNDANCY_GROUP)
- lib60870-C: add support for server allowing multiple clients using the application layer (new mode where each client connection is a redundancy group)
- lib60870-C: limit the number of allowed client connection (T104Slave_setMaxOpenConnections)
- lib60870-C: only accept single active connection in ServerMode == SINGLE_REDUNDANCY_GROUP
- lib60870-C: enhanced big endian platform detection
- lib60870-C: CS104 slave/server: added support for ConnectionRequestHandler
- lib60870-C: Socket_getPeerAddress replaced by Socket_getPeerAddressStatic to avoid dynamic memory allocation
- lib60870.NET: server support for multiple clients with separate ASDU queues (added ServerMode property)
- lib60870.NET: server - added MaxOpenConnections property
- lib60870.NET: server - added ConnectionRequestHandler
- lib60870.NET: Added RawValue properties to SetpointCommandNormalized and MeasuredValueNormalized, additional constructors with short values
- lib60870.NET: ScaledValue adds proporty to get/set short value
- lib60870.NET: fixed tests project dependencies
- lib60870.NET: fixed bug in BitString32
- lib60870-C: fixed month bug in CP56Time2a conversion functions

Changes to version 0.9.4
------------------------
- added length check when adding information objects to ASDUs --> changed signature of ASDU_addInformationObject
- lib60870-C: added TARGET=UCLINUX-XPORT to compile for Lantronix XPORT PRO
- lib60870-C: added CauseOfTransmission_toString function
- lib60870.NET: fixed bug in parsing of MeasuredValueNormalizedWithoutQuality when SEQ = 1
- added all missing timeout handling for master and slave side
- lib60870.NET: added client side ConnectionStatistics
- lib60870.NET: client socket uses Poll instead of read timeout
- lib60870.NET: added TestCommand ASDU
- lib60870.NET: client - some refactoring - added ASDU queue for congestion handling
- lib60870.NET: fixed constructors for StepPosition information objects (added quality)
- lib60870.NET: Added missing GetEncodedSize in SinglePointWithCPxxx objects
- lib60870.NET: added constructors and set properties for CP24Time2a
- lib60870-C: implemented BufferFrame to enable ASDU and IO encoding to arbitrary memory buffers
- lib60870-C: slave - replaced ASDU queue by queue consisiting of buffers of encoded ASDUs
- lib60870.NET: fixed bug in encoding of sequence of information objects
- lib60870.NET: fixed bug in EventOfProtectionEquipment
- lib60870.NET: added public constructor for CP16Time2a
- lib60870.NET: added encoding tests (with maximum number of information objects in ASDU w/wo sequence of information objects)
- lib60870.NET: fixed bug in StatusAndStatusChangeDetection
- lib60870.NET: ASDU parser - added header length check


Changes to version 0.9.3
------------------------
- lib60870.NET: changed visibility of InformationObject.Encode method to internal
- lib60870.NET: added public Constructor Encoding functions for PackedOutputCircuitInfo, PackedStartEventsOfProtectionEquipment, EventOfProtectionEquipment
- lib60870.NET/lib60870-C: Added parsing support for sequence for information objects for all data messages in monitoring direction (despite the fact that this should not happen according to IEC 60870-5-101) 

Changes to version 0.9.2
------------------------
- lib60870-C: changed to select based read at client side
- lib60870.NET: extended STARTDT/STOPDT handling
- lib60870.NET: changed signature of ConnectionHandler
- lib60870-C: added functions to bind to local IP address and TCP port
- lib60870-C: default bind to address "0.0.0.0"
- lib60780-C: fixed StopDT bug
- lib60870-C: fixed C99 incompatibilities in cpXXtime2a.c
- lib60870-C: added support for M_EI_NA_1 message (end of initialization)
- lib60870-C: DoublePointWithCP56Time2a_getFromBuffer corrected parsing of time stamp
- lib60870-C: SingleCommandWithCP56Time2a_getFromBuffer corrected parsing of time stamp
- lib60870-C: SinglePointWithCP56Time2a_getFromBuffer corrected parsing of time stamp
- lib60870-C: StepPositionWithCP56Time2a_getFromBuffer corrected parsing of time stamp
- lib60870-C: DoublePointWithCP24Time2a_getFromBuffer corrected parsing of time stamp
- lib60870-C: SinglePointWithCP24Time2a_getFromBuffer corrected parsing of time stamp
- lib60870-C: corrected parsing of double point information
- lib60870-C: corrected parsing of some data types when sent as sequence of information objects
- lib60870-C: client/master: extended STARTDT/STOPDT handling; changed connection handler signature to indicate STARTDT_CON/STOPDT_CON messages