- Release 1.1-9 is on CRAN now. There are no major user-visible changes.
- Some improvements to , including the ability to simulate; note that is still somewhat unstable, e.g. for models with additional arguments such as or .
- Bug fixes to for models with orthogonal polynomial/spline bases, and to models with offsets and weights
- Otherwise, see the NEWS file (or
`news(Version=="1.1.9",package="lme4")`

).

- Efficient for large data sets, using algorithms from the Eigen linear algebra package via the RcppEigen interface layer.
- Allows arbitrarily many nested and crossed random effects.
- Fits generalized linear mixed models (GLMMs) and nonlinear mixed models (NLMMs) via Laplace approximation or adaptive Gauss-Hermite quadrature; GLMMs allow user-defined families and link functions.
- Incorporates likelihood profiling and parametric bootstrapping.

- From CRAN (stable release 1.0.+)
Development version from Github:

(This requires`library("devtools"); install_github("lme4/lme4",dependencies=TRUE)`

`devtools`

>= 1.6.1, and installs the "master" (development) branch.) This approach builds the package from source, i.e.`make`

and compilers must be installed on your system -- see the R FAQ for your operating system; you may also need to install dependencies manually. Specify`build_vignettes=FALSE`

if you have trouble because your system is missing some of the`LaTeX/texi2dvi`

tools.Usually up-to-date development binaries from

`lme4`

r-forge repository:`install.packages("lme4", repos=c("http://lme4.r-forge.r-project.org/repos", getOption("repos")[["CRAN"]]))`

(these source and binary versions are updated manually, so may be out of date; if you believe they are, please contact the maintainers).

It is possible to install (but not easily to check) `lme4`

at least as recently as 1.1-7.

- make sure you have
*exactly*these package versions:`Rcpp`

0.10.5,`RcppEigen`

3.2.0.2 - for installation, use
`--no-inst`

; this is necessary in order to prevent R from getting hung up by the`knitr`

-based vignettes - running
`R CMD check`

is difficult, but possible if you hand-copy the contents of the`inst`

directory into the installed package directory ...

`lme4.0`

`lme4.0`

is a maintained version of lme4 back compatible to CRAN versions of lme4 0.99xy, mainly for the purpose of*reproducible research and data analysis*which was done with 0.99xy versions of lme4.- there have been some reports of problems with
`lme4.0`

on R version 3.1; if someone has a specific reproducible example they'd like to donate, please contact the maintainers. - Notably,
`lme4.0`

features`getME(<mod>, "..")`

which is compatible (as much as sensibly possible) with the current`lme4`

's version of`getME()`

. - You can use the
`convert_old_lme4()`

function to take a fitted object created with`lme4`

<1.0 and convert it for use with`lme4.0`

. It currently resides on R-forge, and you should be able to install it with

`install.packages("lme4.0", repos=c("http://lme4.r-forge.r-project.org/repos", getOption("repos")[["CRAN"]]))`

(if the binary versions are out of date or unavailable for your system, please contact the maintainers).