> ## Documentation Index > Fetch the complete documentation index at: https://devzone.nayax.com/llms.txt > Use this file to discover all available pages before exploring further. # Marshall Java SDK Release Notes > Track Marshall Java SDK changes as they ship. Nayax logs Marshall Java SDK changes on this page as they ship. Subscribe to the RSS feed using the icon at the top of the page to get notified of new entries. Release notes are organized into two categories to help you evaluate the impact of each update: * **Improvements**: New APIs, expanded feature support, and performance enhancements. * **Fixes**: Resolved bugs and reliability improvements. Some features in this version require VPOS version 4.0.8.23-RC3 or newer. This version spans patches 0.1.6.01 through 0.1.6.23. ### Pre-authorization amount config Added the `pre_auth_amount_config` (0x8c) vend sub-command, including the message class, decode/encode support, a factory method, and event handling in the public API. The demo application now includes a menu option to test pre-authorization amount configuration. *** ### External reader and display control Added an external reader command and extended the [display control](/docs/integrate-pos-device/marshall/additional-resources/marshall-display) API to support additional layouts. * The display control API signature now takes a `layout_t` instance directly. * The SDK version string now also reports the SDK language. *** ### Multi-vend, multi-session, and pricing Added `long_price` support, a 4-byte price capability relevant for VPOS Media. * Fixed the display of negative prices. * Multi-session now works together with multi-vend in the same session. * Added a `final_price` field to `onSessionInfo`. * Real-time price changes are now supported in always-idle mode, even after the reader is already enabled. * The SDK gained file-system management support, since VPOS now provides those services. *** ### Transfer data and QR/third-party authorization Site ID and brand name are now transferred to the machine through [transfer data](/docs/integrate-pos-device/marshall/additional-resources/marshall-ontransferdata). * Added a brands-selection bit for the Japanese market. * Added support for the QR-code card type and third-party authorization for QR-code readers. * Added a technician-mode command to open the door remotely. *** ### Vend and session API improvements `vend_request` and `close_session` now return a boolean value, with a sanity check that price does not exceed the permitted amount (65k when `long_price` is disabled). * Machine sub type can now be set explicitly instead of being hard-coded. * `vend_session_data_t` now exposes all nullable fields, so the caller can tell whether a value was assigned. * The VPOS serial number is now provided as a correctly arranged string instead of raw bytes. *** ### Low-level serial and internal cleanup The SDK no longer bundles `lowlevel_serial.java` directly. Instead, you inject a `serial_port_i` implementation (a certified FTDI and PC-port implementation is provided). * Removed a false warning on `vmc_vend_t` when no callback handler was registered, replacing it with a null check shared between `marshall_sdk` and `marshall_master_sdk`. * Optimized `eth_port` logging. ### Link and retransmission reliability Fixed a missed-ack issue that stopped keepalive and the related link-down issue. * Fixed a race condition between the rx and tx threads on `m_pending_tx_msg` access. * Eliminated false retransmissions. * Improved [`vmc_link`](/docs/integrate-pos-device/marshall/methods-functions/link-and-events-configuration) buffer management to prevent a possible retransmission and frame loss. * Fixed the `session_end` timeout expiring too soon, which previously caused `reader_always_on` to fire early. *** ### Message encoding and decoding Fixed several [message encode/decode bugs](/docs/integrate-pos-device/marshall/methods-functions/data-structures): * `msg_remote_selection_t` encode was an empty stub; now encodes all fields (funds available, payment media ID, payment type, payment data, item number, item options). * `msg_setup_max_min_prices_t` encode was missing its sub-command byte and had a currency-code encoding typo; both are fixed. * `msg_expansion_t` now null-checks the body before decode/encode. * `msg_mdb_rsp_t` decode now correctly instantiates `msg_ftl_retry_deny_t`. * Fixed `fw_info` string copy, which could append garbage to the end of strings. * Fixed a `msg_alert` string decode error. * Fixed an encoding bug affecting multi-session multi-vend frames. * Fixed incorrect session ID encoding in `vend_multi_close_session` and multi-vend multi-session close. * Fixed a frame-size detection issue affecting varying Marshall message sizes. * Fixed a typo in `marshall_func_code_transfer_data`. *** ### Vend and session safeguards Fixed the reader state command so it also works in always-idle mode. * Added protection against vend, socket, and general actions being issued when there is no link. * Fixed a bug where card info from a previous session was not cleared once a session completed. ### Version history Every earlier Java SDK patch, condensed to one line. See the current version above for full detail and links. | Version | Summary | | ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | 0.1.5.27 | Fixed a re-transmission bug where two packets arriving at once could be lost, plus fixes in `mdb_rsp` parsing and `lowlevel_serial` buffer management | | 0.1.5.26 | Added `session_id` to `vend_session_t` for multi-session reference, more logging, fixed a `msg_display_event_t` parsing error that skipped the user callback | | 0.1.5.25 | Fixed `card_balance` decoding, transfer\_data parsing crashes, and final\_price parsing; added logs to decoded transfer\_data fields | | 0.1.5.24 | Fixed a stall/deadlock while waiting for `end_session`, added transfer data messages throughout the transaction, added SDK configuration logging | | 0.1.5.23 | Fixed an undefined state machine state when `on_begin_session` arrived without a session actually starting | | 0.1.5.22 | Logs a possible exception in case it occurs | | 0.1.5.20-21 | Fixed a possible crash when losing communication while sending `reader_enable`; cleaned up logs | | 0.1.5.19 | Fixed a race condition between rx/tx threads causing retransmission of an already-acked packet; improved log readability | | 0.1.5.18 | Fixed e-receipt on multi-session setups; can now switch to info session on always-idle setups | | 0.1.5.17 | Added check-balance session type, card sub type and card balance transfer\_data, and vend discount/final price calculation | | 0.1.5.16 | Fixed item price/code API type (integer to short); fixed a crash when cancelling a session after card presented but before vend requested | | 0.1.5.15 | Fixed session cancel on always-idle mode and unfilled `transaction_id_len`; `session_status` is now filled by the SDK; optimized `low_level_serial` CPU usage | | 0.1.5.14 | Dumps packets on rx re-arrangement for debugging; improved `lowlevel_serial` handling under stress | | 0.1.5.13 | Added `vend_status(bool)` for explicit vend success, fixed a vend-cancel timing bug, added total charged/discount on the session, absolute POSIX timestamps in logs, and an aux logging callback | | 0.1.5.12 | `onStatus` gained an extra data parameter, added `device_not_available_reason` enums, fixed faulty transfer\_data parsing, improved sample app status reporting | | 0.1.5.11 | Added `Log.console(boolean)`, new transfer\_data fields (firmware versions), new device status enums, and the `onSessionTimeout(id)` event | | 0.1.5.10 | Fixed vend-deny persist mode staying on after successful transactions; added `unit_of_measure` enum values and new device status enums | | 0.1.5.9 | Fixed `fw_info` field arrangement and a vend session status request bug; improved `low_level_serial` link reliability; added remote vend support | | 0.1.5.8 | Fixed `vmc_socket` busy/retransmit timeout handling | | 0.1.5.7 | Fixed a race condition on user cancel right after a card swipe, a `lowlevel_serial` hang on faulty packet length, and a `vmc_socket` busy-modem retransmit bug | | 0.1.5.6 | Removed the EV extension, fixed minor API bugs and a CPU starvation detection print bug | | 0.1.5.5 | Aligned with Marshall 3.0: session status query, reader state API, entry type enum, QR e-receipt, and a device Marshall-version query | | 0.1.5.4 | Fixed a UI API bug, improved CPU profiling, added VMC info fields to `fw_info`, limited multi-vend products to avoid buffer overflow | | 0.1.5.3 | Added VMC info fields to `fw_info`, limited multi-vend products to avoid buffer overflow | | 0.1.5.2 | Added CPU monitoring for starvation debugging; logs the packet byte stream on CRC error | | 0.1.5.1 | Fixed a UI event callback API bug | | 0.1.5.0 | Added the `onStatus` vend callback and updated close-session status messages | | 0.1.4.8 | Updated to the latest Marshall spec, adding product code and product price TLV fields | | 0.1.4.7 | Enabled multi-instance SDK use, connecting several VPOSes to a single VMC machine | | 0.1.4.6 | Special encoding handling for Mifare card UIDs | | 0.1.4.5 | Improved MSR handling for cards encoded as integer or ASCII string | | 0.1.4.4 | Updated the EV extension; `onReady()` now returns the ended session; renamed `requestTime`/`setDisplayText`; added display control to `vmc_general` | | 0.1.4.2 | Updated the sample application's paymarket demo | | 0.1.4.1 | Added log redirection to a file stream; fixed an invalid date from `get_transaction_id()` in `onTransactionInfo` | | 0.1.4.0 | Added a serial packet dump-level parameter and a vend-denied policy parameter | | 0.1.3.5 | Updated to the latest Marshall protocol; link establishment now reports merchant ID, terminal ID, and machine location; sample app got multi-session/multi-vend demos | | 0.1.3.4 | Fixed an always-idle bug requiring the reader to stay enabled | | 0.1.3.3 | Fixed a crash on the `alert` API; fixed `reader_always_on` to apply only when always-idle is explicitly disabled | | 0.1.3.2 | Added a debug flag to silence log output and always-idle sample code | | 0.1.3.1 | Updated `libjserial` in the demo application | | 0.1.3.0 | Reorganized sample code and added documentation to the folder | | 0.1.2.9 | Fixed the always-on feature, which had been removed by mistake | | 0.1.2.8 | Minor cleanup; added the paymarket machine type; changed the EV-charger machine type | | 0.1.2.7 | Added socket MTU/timeout configuration, Marshall protocol 2.0 support, always-idle MDB mode, a comm-timeout fix, and a fund-available conversion fix | | 0.1.2.6 | Added an SDK version method, a TCP socket sample, machine type configuration, and improved logging | | 0.1.2.5 | Improved socket handling, removed a false mismatch warning, added a lowlevel reset on CRC error for reliability | | 0.1.2.4 | Fixed a link bug transmitting from an empty queue; SDK now ships as a `.JAR` with a demo application | | 0.1.2.3 | Updated the pay API | | 0.1.2.2 | Added transfer\_data structure parsing on vend sessions for readable data; updated the sample application | | 0.1.2.1 | Improved logging, added a multi-vend example, added the `multi_vend_support` flag, fixed an `onReady` API bug | | 0.1.2.0 | Unified the multi-vend API into a single `vend_request` for both single and multi-vend cases | | 0.1.1.6 | Handles async socket-close and session-close requests from VPOS; fixed cancel/close timing bugs | | 0.1.1.5 | Reports quantity to DCS (requires VPOS 4.0.1.5 rc9+); added a transaction ID report API | | 0.1.1.4 | Aligned close session to the new format | | 0.1.1.3 | Fixed model/version reporting to DCS; separated the keep-alive timer from the configured timeout | | 0.1.1.2 | Added link statistics, fixed a tight-timing retransmission issue and a buffer-index parsing bug | | 0.1.1.1 | Fixed issues in the low-level serial template file | | 0.1.1.0 | Fixed a re-transmit index bug | | 0.1.0.9 | Handles piggy-back Marshall messages | | 0.1.0.8 | Improved `lowlevel_serial` and response time during heavy socket work | | 0.1.0.7 | Added multi-vend support, a prepaid `pay` API, and CC last-4-digits transfer data | | 0.1.0.6 | Fixed a rare high-load bug causing out-of-order Marshall messages | | 0.1.0.5 | Added the `reader_always_on` configuration parameter | | 0.1.0.4 | Added a cash sale notification API and link event callbacks; fixed an incorrect session status bug | | 0.1.0.3 | Added socket callbacks for session control and display message/alert/time-request messages | | 0.1.0.2 | Moved `lowlevel_serial` outside the SDK as an application-specific concern; added configuration reporting to the vending client | | 0.1.0.1 | Fixed an FTP socket closing issue; added VPOS configuration notification for the client |