Changes in R 4.0–4.1

We give a selection of the most important changes in R 4.1.0. Some statistics on source code commits and bug tracking activities are also provided.

Tomas Kalibera (

Czech Technical University, Czech Republic

) , Sebastian Meyer (

Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany

) , Kurt Hornik (

WU Wirtschaftsuniversität Wien, Austria


1 R 4.1.0 selected changes

R 4.1.0 (codename “Camp Pontanezen”) was released on 2021-05-18. The following gives a selection of the most important changes.

2 R 4.1.0 code statistics

From the source code Subversion repository, the overall change between April 25, 2020 and May 28, 2021 (so between R 4.0.0 and R 4.1.0) was: 33,000 added lines, 14,000 deleted lines and 1000 changed files. This is rounded to thousands/hundreds and excludes changes to common generated files, bulk re-organizations, etc. (translations, parsers, autoconf, LAPACK, R Journal bibliography, test outputs, Unicode tables, incorporated M4 macros). This change is slightly bigger than that between R 3.6.0 and R 4.0.0 (24% more insertions, 10% more deletions, 4% more changed files), see News and Notes from the December 2020 issue of the R Journal.

Figure 1 shows commits by month and weekday, respectively, counting line-based changes in individual commits, excluding the files as above. The statistics are computed the same way as in the previous issue, hence allowing direct comparisons, but monthly statistics are impacted by the release date which varies across versions, hence impacting the numbers for April and May. The statistics cover code directly committed to the R-devel trunk, plus commits from the R-defs branch (graphics code from Paul Murrell). The latter was merged into R-devel in July 2020, but the statistics is based on months/days the original commits were made to R-defs, including from December 2019.

graphic without alt textgraphic without alt text

Figure 1: Commit statistics by month (left) and weekday (right) during R 4.1.0 development. *Note that the counts for April 2020 and May 2021 do not cover full months. Commits from December 2019 represent work of Paul Murrell on the later merged R-defs branch.

We observe an activity peak just after the release of R 4.0.0, a minimum in October 2020, and otherwise relatively stable amounts of code changes. The large numbers in May/June do not seem to follow a general pattern: here Paul Murrell did most of his changes on graphics. The right-hand plot shows that there is still a number of contributions even during the weekends.

3 R 4.1.0 bugs statistics

Summaries of bug-related activities during the development of R 4.1.0 (from April 25, 2020 to May 18, 2021) were derived from the database underlying R’s Bugzilla system. Figure 2 shows statistics of reported/closed bugs and number of added comments (on any bug report) by calendar month and weekday, respectively. Deviating from the previous issue, new bug reports (comment 0) are not counted as comments, so these numbers cannot be compared directly. Note that monthly statistics are impacted by truncation at the release dates in April 2020 and May 2021, respectively.

Comments are added by reporters of the bugs, R Core members and external volunteers. When a bug report is closed, the bug is either fixed or the report is found invalid. In principle, this can happen multiple times for a single report, but those cases are rare. Hence the number of comments is a measure of effort (yet a coarse one which does not distinguish thorough analyses from one-liners) and the number of bug closures is a measure of success in dealing with bugs.

R 4.1.0 was released by about 3 weeks later than usual, so the period which is summarized is also longer. The bug-related activities have still increased much more than what could be explained by that: about 17% more bugs closed than for (during development of) 4.0.0, but 55% more bugs reported). The increase from 3.6.0 to 4.0.0 was 45% more bug reports and 92% more bugs closed.

There was a significant increase in the number of comments following a blog post of Tomas Kalibera and Luke Tierney, published October 9, 2019 (so during development of 4.0.0), asking the R community for help with the bugs. The rate of comments stayed relatively high until now, so for the development of 4.1.0. This increased activity also came with more bug reports and more bugs closed. Initially, more bugs were closed than reported (4.0.0 development), but this changed during 4.1.0. It may be that the bugs fixed initially with the help of external volunteers were the older ones easy to handle, but now there is space for external volunteers to help with the new/harder ones.

graphic without alt textgraphic without alt text

Figure 2: Bug tracking activity by month (left) and weekday (right) during R 4.1.0 development. *Note that the counts for April 2020 and May 2021 do not cover full months.

From the numbers by weekday in the right panel of Figure 2 we see that the R community still keeps working during the weekends. Still, the overall bigger bug-related activity seems relatively more reduced during the weekends than during 4.0.0 and 3.6.0 development.

4 Acknowledgements

Tomas Kalibera’s work on the article and R development has received funding from the Czech Ministry of Education, Youth and Sports from the Czech Operational Programme Research, Development, and Education, under grant agreement No.CZ.02.1.01/0.0/0.0/15_003/0000421, from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme, under grant agreement No. 695412, and from the National Science Foundation award 1925644.


This article is converted from a Legacy LaTeX article using the texor package. The pdf version is the official version. To report a problem with the html, refer to CONTRIBUTE on the R Journal homepage.


Text and figures are licensed under Creative Commons Attribution CC BY 4.0. The figures that have been reused from other sources don't fall under this license and can be recognized by a note in their caption: "Figure from ...".


For attribution, please cite this work as

Kalibera, et al., "Changes in R 4.0--4.1", The R Journal, 2021

BibTeX citation

  author = {Kalibera, Tomas and Meyer, Sebastian and Hornik, Kurt},
  title = {Changes in R 4.0--4.1},
  journal = {The R Journal},
  year = {2021},
  note = {},
  volume = {13},
  issue = {1},
  issn = {2073-4859},
  pages = {638-640}