I am trying to run DADA2 on my local machine, and for install I need Biostrings >=2.42.1. However, whenever I try to update Biostrings it automatically tries URL 'http://bioconductor.org/packages/3.0/bioc/src/contrib/Biostrings_2.34.1.tar.gz'. I've tried upgrading Bioconductor and RStudio, but neither helped. I have also tried downloading the tar.gz files for Biostrings 2.46.0 and installing it with both the the GUI and 

install.packages("~/path/to/Biostrings/",
                 repos = NULL,
                 type = "source")

But doing either led to Biostrings failing to be compiled. Any ideas on how I can successfully upgrade Biostrings, or get around this dependency somehow and install DADA2 regardless? Thanks!

p.s. Sorry, I'm still very new to R....

Here is my session info:

R version 3.4.2 (2017-09-28)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 14.04.5 LTS

Matrix products: default
BLAS: /usr/lib/openblas-base/libblas.so.3
LAPACK: /usr/lib/lapack/liblapack.so.3.0

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C               LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8    
 [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8    LC_PAPER=en_US.UTF-8       LC_NAME=C                 
 [9] LC_ADDRESS=C               LC_TELEPHONE=C             LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] BiocInstaller_1.16.5

loaded via a namespace (and not attached):
[1] compiler_3.4.2 tools_3.4.2    yaml_2.2.0  

Bioconductor package versions are tightly associated with the R version, so you can't get new versions of packages to install on old versions of R. You should upgrade to R-3.5.x (whatever is the current minor version) and then use biocLite to install the packages you need.