SimpleLPR

License Plate Recognition SDK

SimpleLPR Change Log

Track the evolution of SimpleLPR with version history and release notes

SimpleLPR 3.6.4.0 Latest
Released July 24, 2026
✨ New Features
  • Added support for New Zealand license plates, including current (2001-present) and previous (1964-2001) passenger series, motorcycle, moped, tractor, trailer, and dealer/trade formats, with recognition of both black-on-white and light-on-dark ("black plate") variants
🔧 Improvements
  • Revised the Australia license plate coverage across all eight states and territories (ACT, New South Wales, Northern Territory, Queensland, South Australia, Tasmania, Victoria, and Western Australia) and the national schemes (military, diplomatic, National Heavy Vehicle), spanning standard passenger, motorcycle, trailer, taxi, bus, government, diplomatic, consular, and special-interest/historic/heritage vehicle categories
  • Extended the Colombia motorcycle template (AAA-NNA) to accept the full A-M range for the final letter, covering recently issued series
🐛 Bug Fixes
  • Fixed RTSP video sources not closing the network connection when released: disposing an 'IVideoSource' now performs the RTSP teardown and closes the socket immediately, so cameras no longer accumulate stale sessions and single-session cameras can be reopened right away
  • Fixed file-based video sources keeping the input file locked after release; the file can be deleted or moved as soon as the source is disposed
  • Fixed 'IVideoSource.reconnect' failing to recover after a network error; the previous connection is now fully torn down before reconnecting
  • Live video sources now wait for a keyframe after opening or reconnecting and discard corrupt frames, eliminating the gray or smeared imagery previously seen at the start of live streams
  • Fixed crash when the engine was disposed before video sources, processors, pools, trackers or frames created from it (.NET: NullReferenceException inside 'nextFrame'; Python: hard crash). All objects now remain fully functional regardless of disposal order, and errors remain retrievable after the engine is released
  • Fixed stale errors being misattributed to 'IVideoSource.nextFrame': the end of a stream is now always reported as a clean end-of-stream instead of an unrelated earlier error, and valid frames are no longer discarded (and, in .NET, leaked) by spurious exceptions
  • 'IVideoFrame.saveAsJPEG' now reports failures by throwing an exception; previously a failed save was completely silent
  • .NET video frames now report their native pixel-buffer size to the garbage collector, preventing native memory from ballooning when frames are not disposed promptly
  • All C API functions now validate their arguments: a null handle returns the documented failure value and records a retrievable E_POINTER error instead of crashing inside the library
  • Python: the interpreter lock (GIL) is now released during blocking and CPU-intensive calls ('nextFrame', 'analyze', 'launchAnalyze', 'pollNextResult', engine creation, ...), keeping multi-threaded Python applications responsive while the library works
  • Python: fixed 'IProcessorPool.launchAnalyze' raising a spurious error and leaking memory instead of returning False when no processor became available within the timeout, and fixed image-buffer requests returning wrong request identifiers from 'pollNextResult'
SimpleLPR 3.6.3.0
Released December 17, 2025
✨ New Features
  • Added comprehensive support for Uganda license plates, including standard formats (1999-2023), government ministries, military, police, diplomatic, and specialized vehicle categories
  • Added wrappers for Python 3.13 and 3.14
🔧 Improvements
  • Enhanced Ukraine template with support for electric vehicle plates using Latin alphabet series (YA-YZ), and diplomatic plates (D + 6 digits format)
🐛 Bug Fixes
  • Fixed two-line plate recognition issue where lines with significantly different character heights were not being grouped as a single plate
SimpleLPR 3.6.2.0
Released September 8, 2025
🐛 Bug Fixes
  • Fixed executable stack flag in libSimpleLPR3.so that prevented the library from loading in Docker containers and other security-hardened environments. The library now properly builds with the 'noexecstack' linker flag
  • Fixed coordinate reference issue in 'IProcessor.analyze' and 'IProcessorPool.launchAnalyze' methods when processing video frames with a Region of Interest (RoI). Results now correctly return coordinates relative to the full frame rather than the RoI origin
  • Resolved thumbnail extraction issue in 'IPlateCandidateTracker' where 'representativeThumbnail' would return incorrect image regions when frames were processed with RoI constraints
SimpleLPR 3.6.1.0
Released August 22, 2025
✨ New Features
  • Added comprehensive support for Malta license plates, including standard formats, government vehicles, taxis, and special vehicle categories
🔧 Improvements
  • Enhanced Andorra template with support for temporary (MT), dealer (PROVA), special vehicles, and personalized plates (2-5 characters)
  • Enhanced Mozambique template to support 'AA-NNN-AA' private vehicle plates and single-line diplomatic plate formats
  • Enhanced Russia template with transit/export plate support, including square two-line variants, paper transit plates ('AA NNNA NN'), and military trailer configurations
  • Upgraded GPU processing infrastructure to CUDA 12.9 for improved performance and compatibility
🐛 Bug Fixes
  • Resolved potential deadlock issue when processing multiple concurrent streams with varying input frame dimensions under CUDA acceleration
SimpleLPR 3.6.0.0
Released June 5, 2025
✨ New Features
  • Added 'IPlateCandidateTracker' class for tracking license plates across multiple video frames, providing temporal correlation resistant to OCR misreadings and partial detections
  • Added comprehensive samples in C#, Python, and C++ demonstrating the new plate tracking functionality
  • Added new interactive WPF sample application that displays captured license plates in real-time during video processing
🔧 Improvements
  • Updated Russia template to support three-digit region codes (1xx, 2xx, 3xx, 5xx, 6xx, 7xx, 9xx series) as per current regional coding system
  • Enhanced Azerbaijan template with support for diplomatic ('NNN A NNN'), motorcycle ('NN A NNN'), and newer 'A NNN AA' format license plates
SimpleLPR 3.5.9.0
Released February 19, 2025
✨ New Features
  • Added 'IProcessorPool' class to enable concurrent license plate recognition operations, improving throughput for multi-image processing scenarios
🐛 Bug Fixes
  • Fixed runtime dependency error caused by missing "libdl.so" shared library on Ubuntu 24.04 systems
  • Solved an issue where the evaluation mode was not being properly activated on specific Linux distribution profiles
SimpleLPR 3.5.8.0
Released December 24, 2024
✨ New Features
  • Added 'VideoSource' class for basic frame acquisition from video files and RTSP streams
  • Added a new overload to 'IProcessor.analyze' that accepts video frames from a 'VideoSource' instance
SimpleLPR 3.5.7.0
Released August 1, 2024
✨ New Features
  • Added wrapper for Python 3.12
SimpleLPR 3.5.6.0
Released June 3, 2024
🐛 Bug Fixes
  • Letter 'Q' is now correctly recognized in license plates from Azerbaijan
SimpleLPR 3.5.5.0
Released July 3, 2023
✨ New Features
  • Added support for license plates from Andorra
  • Added support for the latest 'AA AA NNN' license plate format introduced in 2022 for Hungary
SimpleLPR 3.5.5.0
Released July 3, 2023
✨ New Features
  • Added support for license plates from Andorra
  • Added support for the latest 'AA AA NNN' license plate format introduced in 2022 for Hungary
SimpleLPR 3.5.4.0
Released May 25, 2023
✨ New Features
  • Added wrappers for Python 3.10 and Python 3.11
  • Added support for license plates from Turkmenistan
  • Added support for Bharat pan-Indian license plates
SimpleLPR 3.5.3.0
Released March 15, 2023
🐛 Bug Fixes
  • Added missing light on dark license plate templates for India
  • Fixed the Mercosur motorcycle license plate templates from Brazil
SimpleLPR 3.5.2.0
Released February 28, 2023
✨ New Features
  • Added support for license plates from Mozambique
  • Added support for vintage, temporary, and diplomatic license plates from Spain
SimpleLPR 3.5.1.0
Released January 5, 2023
✨ New Features
  • Added new overloads to 'IProcessor.analyze' that take a JPEG, PNG or TIFF encoded image from a buffer in memory or a 'Stream' object
🔧 Improvements
  • Floating point exceptions are now disabled during execution of all variants of the 'IProcessor.analyze' call
  • Project migrated to Visual Studio 2022
  • Dependency libraries have been upgraded to their latest version
  • Dropped support for Windows 7 and Windows 8
SimpleLPR 3.5.0.0
Released November 21, 2022
✨ New Features
  • Added wrappers for Python 3.8 and Python 3.9
  • The 'SimpleLPR3.dll' assembly now targets .NET Standard 2.0 for better interop with the .NET Framework, .NET Core, and .NET

For the complete version history, please refer to the full documentation.

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