Changes

💡 New Features

• [python] add return_cvbooster flag to cv func and publish _CVBooster (#283,#2105,#1445) @momijiame (#3204)
• [R-package] make package installable with CRAN toolchain (fixes #2960) @jameslamb (#3188)
• feat: Change locking strategy of Booster, allow for share and unique locks @JoanFM (#2760)
• feature importance type in saved model file @guolinke (#3220)
• [R-package] Interface for interaction constraints @btrotta (#3136)
• adding sparse support to TreeSHAP in lightgbm @imatiach-msft (#3000)
• Adding static library option @dpayne (#3171)
• Interaction constraints @btrotta (#3126)
• [R-package] Add support for R 4.0 (fixes #3064, fixes #3024) @jameslamb (#3065)
• [python][scikit-learn] add new attribute for used number of features @a-wozniakowski (#3129)
• redirect log to python console @guolinke (#3090)
• Path smoothing @btrotta (#2950)
• [SWIG][mmlspark] allow allocating more than int max array @imatiach-msft (#2859)
• Support UTF-8 characters in feature name again @henry0312 (#2976)
• [python] Re-enable scikit-learn 0.22+ support @StrikerRUS (#2949)
• Pr3 monotone constraints splits penalization @CharlesAuguste (#2939)
• [R-package] adding routine registration in R package (fixes #1910) @jameslamb (#2911)
• [R-package] Use Rprintf for logging in the R package (fixes #1440, fixes #1909) @jameslamb (#2901)
• Improving monotone constraints ("Fast" method; linked to #2305, #2717) @CharlesAuguste (#2770)
• [python] handle RandomState object in Scikit-learn Api @lpfann (#2904)
• Debug flags @guolinke (#2825)
• added feature infos to JSON dump @StrikerRUS (#2660)
• Add capability to get possible max and min values for a model @JoanFM (#2737)
• Extremely randomized trees @btrotta (#2671)
• [python] add property: feature_name_ in lgb sklearn api @zhangqibot (#2740)
• Implementation of XE_NDCG_MART for the ranking task @sbruch (#2620)
• [python] Output model to a pandas DataFrame @pford221 (#2592)
• option to disable the shape checking in prediction. @guolinke (#2669)
• added feature importance to JSON dump @StrikerRUS (#2656)
• [python] allow to specify orientation of a tree @StrikerRUS (#2605)
• auc-mu @btrotta (#2567)
• [python] Allow python sklearn interface's fit() to pass init_model to train() @aaiyer (#2447)
• Add more debug logging to show data load progress. @ashok-ponnuswami-msft (#2587)

🔨 Breaking

• [Python] add start_iteration to python predict interface (#3058) @shiyu1994 (#3272)
• [R-package] refactor and improvements to lgb.convert() functions (fixes #2678, #2681) @jameslamb (#3269)
• [R-package] deprecate lgb.prepare() and lgb.prepare2() @jameslamb (#3095)
• [R-package] Add version floor of R 3.5 (fixes #3212) @jameslamb (#3216)
• refactor LGBM_DatasetGetFeatureNames @StrikerRUS (#3022)
• Fix SWIG methods that return char** @AlbertoEAF (#2850)
• Code refactoring for ranking objective & Faster ndcg_xendcg @guolinke (#2801)
• decouple bagging with num_threads @guolinke (#2804)
• remove init-score parameter @guolinke (#2776)
• [python] [R-package] refine the parameters for Dataset @guolinke (#2594)
• Support both row-wise and col-wise multi-threading @guolinke (#2699)
• [ci] indicate support only for the last 3 macOS versions in wheel name @StrikerRUS (#2691)
• removed OpenMP ugly fix for Mojave @StrikerRUS (#2674)
• [python] specify the last supported version of scikit-learn @StrikerRUS (#2637)

🚀 Efficiency Improvement

• Feat/optimize single prediction @AlbertoEAF (#2992)
• Optimize the computation of the cross-entropy ranking loss @sbruch (#3080)
• Speed-up "Split" and some code refactorings @guolinke (#2883)
• speed up FindBestThresholdFromHistogram @guolinke (#2867)
• speed up for const hessian @guolinke (#2857)
• reduce the overhead of OMP_NUM_THREADS in training @guolinke (#2852)
• speed up multi-val bin subset for bagging @guolinke (#2827)
• speed up sub-feature in row-wise parallelism @guolinke (#2764)
• slightly reduce the cost of multi-val bin construct. @guolinke (#2728)
• more efficient sampling k from n @guolinke (#2693)
• support most frequent bin @guolinke (#2689)
• prefetch hint (1.3x speed-up) @guolinke (#2677)

🐛 Bug Fixes

• create buffer for gradients and hessians with goss and customized objective (fixes #3243) @shiyu1994 (#3263)
• update multi-class objective (softmax) @guolinke (#3256)
• Fast single row predict API v2 @AlbertoEAF (#3268)
• [R-package] fix early_stopping_round <= 0 @jameslamb (#3259)
• fix bug in CEGB when reset training data or config @guolinke (#3246)
• fix possible problem in getting number of columns from libsvm file. @guolinke (#3242)
• set num_threads of share_state (#3151) @shiyu1994 (#3238)
• Upcast index to size_t in Refit @jtilly (#3228)
• [python][scikit-learn] Fixes a bug that prevented using multiple eval_metrics in LGBMClassifier @gramirezespinoza (#3222)
• [python] fix early_stopping_round = 0 @guolinke (#3211)
• Fix integer overflow in auc_mu (fixes #3201) @btrotta (#3209)
• Store the true split gain (without subtracting min_split_gain) in tree models (fix Issue #3054) @shiyu1994 (#3196)
• Fix bug with interaction constraints @btrotta (#3189)
• [R-package] [ci] update to R 4.0.2 for Windows CI jobs (fixes #3191) @jameslamb (#3193)
• fix str2double for leaf_weights @guolinke (#3148)
• fix error C3861: '_BitScanReverse': identifier not found @StrikerRUS (#3141)
• [R-package] fix best_score using custom evaluation (fixes #3112) @jameslamb (#3117)
• [R-package] Turn matrix to storage mode "double" @mayer79 (#3140)
• memory corruption fix for distributed data parallel version before SyncUpGlobalBestSplit @imatiach-msft (#3110)
• [R-package] fix issue where early stopping thinks higher MAPE is desirable (fixes #3099) @jameslamb (#3101)
• fix a bug when we set the default score @guanqun (#3114)
• fix MSVC warning about control paths (fixes #3067) @jameslamb (#3068)
• Fixed machine list parsing: s/find_first_of/find @odimka (#3108)
• fix refactoring bug in voting parallel @guolinke (#3089)
• fix goss with constant hessian @guolinke (#3077)
• [docs] update link to GitHub anchor conventions @jameslamb (#3085)
• fix goss bug @guolinke (#3063)
• [R-package] add conda dir for LIBR_CORE_LIBRARY (fixes #3045) @jameslamb (#3046)
• [R-package] CMake fixes to support MSVC @jameslamb (#2963)
• Fix loss computation in rank cross-entropy objective @sbruch (#3031)
• [R-package] fixed best_iter and best_score when training data is passed (fixes #2295, #2525) @jameslamb (#2961)
• [R-package] fix R examples and lgb.plot.interpretation() @jameslamb (#3002)
• Revert "Fix Booster read/write locale dependency (#2891)" @henry0312 (#2980)
• [SWIG][mmlspark] fix seg fault in LGBM_BoosterGetEvalNamesSWIG @imatiach-msft (#2958)
• fix inf in json model dump @StrikerRUS (#2940)
• [R-package] fixed evaluation on valids in lightgbm() (fixes #2915) @jameslamb (#2916)
• Fix IsZero in tree.h @AlbertoEAF (#2932)
• [R-package] fixed handling of multiple evaluation metrics (fixes #2913) @jameslamb (#2914)
• Fix Booster read/write locale dependency @AlbertoEAF (#2891)
• [python] Fix continued train by reusing the same dataset @guolinke (#2906)
• [python] fix the bug when use different params with reference @guolinke (#2907)
• fix ResetConfig in FeatureHistogram @guolinke (#2882)
• fixed cpplint errors and VS project files @StrikerRUS (#2873)
• fix possible bug related num_threads @guolinke (#2876)
• [python] save all param values into model file @StrikerRUS (#2589)
• shrinkage to internal values @guolinke (#2853)
• fix bug in parallel learning @guolinke (#2851)
• don't save num_thread as possible @guolinke (#2839)
• fix bug for multi-val-bin construction @guolinke (#2841)
• fix forced split @guolinke (#2838)
• avoid most_freq_bin to be 0 in categorical features @guolinke (#2824)
• fix index and remove unused includes @StrikerRUS (#2829)
• support larger element size for multi-val bin @guolinke (#2817)
• fix random threshold for categorical features @guolinke (#2802)
• fix bug when nan bin is most freq bin @guolinke (#2811)
• Fix SingleRowPredictor::IsPredictorEqual comparison (invert) @AlbertoEAF (#2799)
• [R-package] Fixed R implementation of upper_bound() and lower_bound() for lgb.Booster @jameslamb (#2785)
• [R-package] fixed R Dataset aliases @StrikerRUS (#2775)
• fix max_depth in CEGB @guolinke (#2751)
• fix subset bug @guolinke (#2748)
• Config static initialization @jcipar (#2743)
• Preventing denormal leaf values @jpkoponen (#2724)
• [python][R-package][docs] fix support of XE_NDCG_MART obj in language wrappers and docs @StrikerRUS (#2726)
• add is_sparse back @guolinke (#2729)
• fix #2696 @sh1ng (#2700)
• [R-package] fixed sorting issues in lgb.cv() when using a model with observation weights (fixes #2572) @jameslamb (#2573)
• [python] fix trees_to_dataframe and enhance test @StrikerRUS (#2690)
• [python] [R-package] Use the same address when updated label/weight/query @guolinke (#2662)
• fix predict with header @guolinke (#2643)
• [python][sklearn] do not modify args in fit function and minor code cleanup @StrikerRUS (#2619)
• [python] Variable Typo: redictor -> predictor @duckladydinh (#2622)
• LightGBM would hang on MPI run if only some nodes have a fatal error. @ashok-ponnuswami-msft (#2600)

📖 Documentation

• [doc] better doc for keep_training_booster @guolinke (#3275)
• [docs] improve params docs @StrikerRUS (#3252)
• typo fix @guanqun (#3174)
• [docs] Improve some phrasing in the installation guide @Lewington-pitsos (#3214)
• [docs] document option to build a static library @StrikerRUS (#3190)
• [docs][scikit-learn] removed duplicated docstrings @StrikerRUS (#3164)
• [ci][docs] fix broken links @StrikerRUS (#3176)
• [R-package] [docs] fix warnings in pkgdown site building @jameslamb (#3086)
• [R-package] [docs] Removed outdated language about the R package @jameslamb (#3070)
• [docs] document one more workaround for CMake and MinGW build and fix typos @StrikerRUS (#3081)
• [docs] Document cmake+MinGW (fixes #3060) @Laurae2 (#3078)
• [docs] updated docs about output values @StrikerRUS (#3037)
• [docs] updated bug report template @jameslamb (#3032)
• [R-package] Remove lgbdl from docs until fix @Laurae2 (#3035)
• [R-package] [docs] remove unnecessary build in test coverage @jameslamb (#3004)
• [docs] update link to Julia wrapper @StrikerRUS (#3021)
• [docs] updated core team list @StrikerRUS (#3001)
• [R-package] [docs] Simplified examples to cut example run time (fixes #2988) @jameslamb (#2989)
• [docs] Add LightGBM Tuner by Optuna links to README.md @Crissman (#2893)
• [docs] add link to blog post about Optuna to Parameters-Tuning.rst @Crissman (#2896)
• [docs] update latest benchmark results @guolinke (#2887)
• [R-package] [docs] Added documentation on lgb.dl() and data.table version (fixes #2715) @jameslamb (#2846)
• fixed cpplint issues and updated docs @StrikerRUS (#2830)
• [docs] Added subsections into param list @StrikerRUS (#2779)
• Better documentation for Contributing @guolinke (#2781)
• [docs] fixed metric_freq param description @StrikerRUS (#2780)
• [docs] removed mentions of sparse_threshold @StrikerRUS (#2758)
• [R-package] clarified error messages and documentation for lgb.get.eval.result() @jameslamb (#2686)
• [R-package][docs] made roxygen2 tags explicit and cleaned up documentation @jameslamb (#2688)
• [R-package] Added instructions for generating R test coverage @jameslamb (#2664)
• [R-package] [docs] Added reference to unofficial R extensions (fixes #2640) @jameslamb (#2670)
• warning for init_score in save_binary @guolinke (#2649)
• [docs] provide link to m2cgen from convert_model_language param description @StrikerRUS (#2591)
• [docs] added link to cuML in external repos section of README @StrikerRUS (#2634)
• [docs] added search key words for artifacts @StrikerRUS (#2631)
• [docs] enhanced description of cat features param @StrikerRUS (#2627)
• [docs] updated records of kaggle competitions @jameslamb (#2621)
• [docs] added link to kubeflow fairing and enhanced parallel guide @StrikerRUS (#2602)

🧰 Maintenance

• [CI] fix R's installation @guolinke (#3279)
• [R-package] move all examples to dontrun() to fix R CMD CHECK notes @jameslamb (#3270)
• [R-package] add some R build files to gitignore @jameslamb (#3271)
• [tests][python][scikit-learn] New unit tests and maintenance @a-wozniakowski (#3253)
• [ci] run Travis and Azure Pipelines only for master branch @StrikerRUS (#3265)
• [R-package] allow R to pick between -fPIC and -fpic for CRAN package @jameslamb (#3261)
• [TYPO] DatasetLoader::ConstructFromSampleData @lcsdavid (#3258)
• remove unnecessary semicolon @jameslamb (#3260)
• [ci] partly remove macOS temp CI fix @StrikerRUS (#3251)
• [R-package] remove duplicated test @jameslamb (#3250)
• update gitignore to ignore files created by clion @zhengruifeng (#3248)
• [R-package] Add tests on lgb.check.eval, lgb.unloader, and lgb.encode.char @jameslamb (#3235)
• [ci] remove unnecessary R_CHECK_FORCE_SUGGESTS in CI scripts @jameslamb (#3240)
• typo fix @guolinke (#3239)
• [SWIG] removed commented code @StrikerRUS (#3233)
• [R-package] add test on importance types @jameslamb (#3231)
• [R-package] factor out {ggplot2} @jameslamb (#3224)
• add rules for tests/ in CODEOWNERS @jameslamb (#3226)
• [ci] bump R 4 version @StrikerRUS (#3225)
• [R-package] remove xlen_t in custom R-to-C++ interface @jameslamb (#3223)
• [R-package] remove unused Suggests dependencies @jameslamb (#3217)
• Remove extra semicolons @AIshb (#3215)
• [ci] [R-package] catch builds that have not updated docs @jameslamb (#3205)
• [ci] bump gcc version for macOS @StrikerRUS (#3208)
• Allow the minimal feature to 1 in column sampling @guolinke (#3197)
• [R-package] [ci] Fix MiKTeX downloads (fixes #3198) @jameslamb (#3199)
• [python][scikit-learn] new stacking tests and make number of features a property @a-wozniakowski (#3173)
• [R-package] fix R CMD check NOTE about leftover files @jameslamb (#3181)
• [ci][docs] added GitHub Actions badge and simplified condition in config @StrikerRUS (#3179)
• [R-package] [ci] cut nrounds in unit tests @jameslamb (#3169)
• [ci] update Boost version @StrikerRUS (#3175)
• [ci] Move R Windows CI to GitHub Actions @jameslamb (#3168)
• [ci] avoid VS warning for R builds @StrikerRUS (#3162)
• [ci][docs] temporarily pin Sphinx version @StrikerRUS (#3157)
• Revert "re-order includes (fixes #3132) (#3133)" @StrikerRUS (#3153)
• [ci] make MiKTeX downloads more reliable @jameslamb (#3124)
• [ci] use GitHub Actions for R CI jobs (fixes #2353) @jameslamb (#3119)
• re-order includes (fixes #3132) @jameslamb (#3133)
• [ci] remove unused environment variable in CI setups @jameslamb (#3125)
• [R-package] move R source files into R-package, reduce duplication in build_r.R @jameslamb (#3087)
• [ci] fix add-apt-repository warning @jameslamb (#3104)
• [R-package] characterize all cmake messages @jameslamb (#3105)
• [R-package] [docs] replace build_r_site.R with pkgdown::build_site() @jameslamb (#3098)
• [ci] bump XCode version at Travis @StrikerRUS (#3097)
• [ci] avoid duplicate AppVeyor builds @jameslamb (#3096)
• [R-package] [ci] Fix CI timeouts for Mac builds on Travis (fixes #3091) @jameslamb (#3092)
• [R-package] fix warnings in tests @jameslamb (#3069)
• [R-package] [docs] remove devtools dependency for docs builds (fixes #3036) @jameslamb (#3072)
• [R-package] speed up installation with Visual Studio @jameslamb (#2965)
• Update CODEOWNERS rule about CMakeLists.txt @jameslamb (#3079)
• removed deprecated code @StrikerRUS (#3073)
• [R-package] added tests on LGBM_BoosterResetTrainingData_R @jameslamb (#3020)
• [python-package] Use set for OS check @jameslamb (#3059)
• typo fix @guanqun (#3055)
• [ci] fix flaky test @StrikerRUS (#3056)
• [docs] update ROCm link in docs @StrikerRUS (#3050)
• [R-package] [ci] Add Windows CI for R package (fixes #2335) @jameslamb (#2936)
• [python][tests] unused and missing imports @jameslamb (#3023)
• [R-package] added tests on LGBM_BoosterRollbackOneIter_R @jameslamb (#3006)
• [R-package] Added tests on LGBM_GetLastError_R @jameslamb (#3005)
• [R-package] Added tests on creating a Booster from a Dataset @jameslamb (#3007)
• [ci] minor CI scripts update @StrikerRUS (#3019)
• [R-package] [ci] added echoing of R CMD check logs to CI @jameslamb (#3009)
• [ci][docs] Fix RTD builds @StrikerRUS (#3015)
• [ci][docs] be compatible with Sphinx 3 @StrikerRUS (#3013)
• [ci] Changed use of strcpy to snprintf (fixes #1990) @jameslamb (#2973)
• [R-package] Updated package metadata in DESCRIPTION @jameslamb (#2993)
• [R-package] Removed unused constant in R_object_helper.h @jameslamb (#2994)
• Update CODEOWNERS @StrikerRUS (#2996)
• more cpp lints @guolinke (#2985)
• [python][ci] start to support Python 3.8 @StrikerRUS (#2713)
• [ci] fixed r-lintr version constraint @StrikerRUS (#2990)
• [R-package] Added unit tests on creating Booster from file or string @jameslamb (#2945)
• fix cpp lint in json11 @guolinke (#2975)
• [ci][docs] downgrade breathe @StrikerRUS (#2982)
• [docs] update URL in docs @StrikerRUS (#2978)
• [ci][docs] downdrage sphinx and fix LaTeX error in R-package tests @StrikerRUS (#2977)
• fixed cpplint errors about string& members @jameslamb (#2929)
• fixed cpplint errors @StrikerRUS (#2971)
• [ci] upgrade to R 3.6.3 in CI @jameslamb (#2969)
• replace built-in assert with own CHECK macro @StrikerRUS (#2938)
• Cleanup MissingType enum constants @AlbertoEAF (#2931)
• [ci] reduce duplication in Python Windows CI @jameslamb (#2962)
• [R-package] [ci] Add option to skip installation in build_r.R @jameslamb (#2957)
• [ci][docs] fixed broken link @StrikerRUS (#2956)
• [ci] changed CRAN mirror to fix failing installs @jameslamb (#2954)
• [R-package] [ci] added check on number of R CMD CHECK notes @jameslamb (#2942)
• changed sprintf uses to snprintf @jameslamb (#2920)
• [R-package] fixed some minor issues with testing on Windows @jameslamb (#2908)
• [R-package] added test on uncovered line of lgb.plot.importance() @jameslamb (#2903)
• [ci] fixed cpplint errors about namespace using-directives @jameslamb (#2927)
• [R-package] fixed NOTE about unrecognized global variable @jameslamb (#2928)
• [ci] fix VS project files @StrikerRUS (#2924)
• [R-package] [ci] added more linters @jameslamb (#2803)
• [R-package] removed duplicated code figuring out build_dir in install.libs.R @jameslamb (#2917)
• [R-package] added command to remove build/ dir in install.libs.R @jameslamb (#2909)
• fix release-drafter.yml @guolinke (#2895)
• [R-package] removed unnecessary flag in tests @jameslamb (#2910)
• fixed cpplint errors and disable warning only for VS @StrikerRUS (#2888)
• [R-package] cleaned up formatting in R C/C++ files @jameslamb (#2844)
• [R-package] Introduce R-specific control of lib_lightgbm @jameslamb (#2837)
• add more bots @guolinke (#2843)
• [ci] fixed cpplint warnings about braces @jameslamb (#2869)
• use specific checks in auto config @StrikerRUS (#2864)
• fix warnings in debug mode about that not all control paths return a value @StrikerRUS (#2866)
• fixed cpplint issues @StrikerRUS (#2863)
• [R-package] [ci] added tests on early_stopping @jameslamb (#2848)
• [docs] update link to MS MPI @StrikerRUS (#2861)
• [R-package] removed unused imports from R-specific lib_lightgbm components @jameslamb (#2845)
• [docs] Fix description according to markdownlint @daikikatsuragawa (#2865)
• [ci] fix R tests for macOS on Azure Pipelines @StrikerRUS (#2856)
• [R-package] added test on training with sparse features @jameslamb (#2847)
• introduced specific CHECKs @StrikerRUS (#2849)
• update lockbot @StrikerRUS (#2842)
• fixed cpplint error about namespace using-directives @StrikerRUS (#2836)
• Update BUG_REPORT.md @guolinke (#2833)
• Add lock bot @guolinke (#2815)
• No LinkTimeCodeGeneration in VS @guolinke (#2812)
• [ci] bump Azure image versions @StrikerRUS (#2822)
• [tests][python] fixed pandas deprecation warning in tests @StrikerRUS (#2819)
• replace std::runtime_error with Log::Fatal @StrikerRUS (#2816)
• Make timer thread-safe @guolinke (#2800)
• fixed cpplint issues @StrikerRUS (#2809)
• fix clang warning for GPU @guolinke (#2807)
• [R-package] [docker] Added ability to build LightGBM in an R container with different R versions @jameslamb (#2787)
• [docs] fixed broken links @StrikerRUS (#2795)
• some code refactoring @guolinke (#2769)
• fixed cpplint issues @StrikerRUS (#2771)
• [python] in sklearn wrapper pass cat features to Dataset constructor @StrikerRUS (#2763)
• fixed cpplint issues @StrikerRUS (#2756)
• Refactoring monotone constraints (linked to #2305) @CharlesAuguste (#2717)
• various minor style, docs and cpplint improvements @StrikerRUS (#2747)
• [ci] avoid Appveyor failures @StrikerRUS (#2753)
• warning for testing col-wise and row-wise @guolinke (#2727)
• no omp_set_nested @guolinke (#2734)
• [python][tests] fixed typo @StrikerRUS (#2732)
• removed AVX2 from VS config and reset PlatformToolset values back @StrikerRUS (#2731)
• [ci] swap compilers back for CI services @StrikerRUS (#2730)
• [python][R-package] removed duplicated code from language wrappers @StrikerRUS (#2606)
• [docs] fix RTD builds due to conda's problems @StrikerRUS (#2725)
• [ci] use raw strings in NuGet helper script @StrikerRUS (#2710)
• [R-package] moved parameter validations up earlier in function calls @jameslamb (#2663)
• [R-package] added test that Dataset$setinfo() converts 'group' input to integer @jameslamb (#2687)
• [R-package] added tests on lgb.plot.importance and clarified documentation @jameslamb (#2692)
• check _mm_prefetch in cmake @guolinke (#2694)
• [R-package] added tests on lgb.prepare function @jameslamb (#2685)
• [R-package] [ci] removed TODOs in code @jameslamb (#2667)
• [R-package] simplified lgb.check.eval() @jameslamb (#2654)
• [R-package] removed function lgb.check.params @jameslamb (#2652)
• [R-package] fixed typo for variable valid_contain_train @jameslamb (#2653)
• [ci] bump XCode version for Travis @StrikerRUS (#2646)
• fixed some cpplint issues @StrikerRUS (#2635)
• [R-package][ci] added CI stage for R package (fixes #2335, fixes #2569) @jameslamb (#2530)
• [docs] fixed broken link in docs @StrikerRUS (#2623)
• [python][R-package] warn users about untransformed values in case of custom obj @StrikerRUS (#2611)
• [docs] fixed broken link in docs @StrikerRUS (#2601)
• fix compile warning for HDFS version @StrikerRUS (#2586)
• bump version for development @StrikerRUS (#2599)