diff --git a/.Rbuildignore b/.Rbuildignore
index e63696ad6..935577358 100755
--- a/.Rbuildignore
+++ b/.Rbuildignore
@@ -1,3 +1,4 @@
+^.*\.RData$
 ^.*\.Rproj$
 ^\.Renviron$
 ^\.Rprofile$
diff --git a/.github/workflows/check.yaml b/.github/workflows/check.yaml
index a956ea258..5fd4f1930 100644
--- a/.github/workflows/check.yaml
+++ b/.github/workflows/check.yaml
@@ -66,8 +66,8 @@ jobs:
           - {os: ubuntu-20.04,   r: '3.5',     allowfail: false, rspm: "https://packagemanager.rstudio.com/cran/__linux__/focal/latest"}
           - {os: ubuntu-20.04,   r: '3.4',     allowfail: false, rspm: "https://packagemanager.rstudio.com/cran/__linux__/focal/latest"}
           - {os: ubuntu-20.04,   r: '3.3',     allowfail: true,  rspm: "https://packagemanager.rstudio.com/cran/__linux__/focal/latest"}
-          - {os: ubuntu-20.04,   r: '3.2',     allowfail: true,  rspm: "https://packagemanager.rstudio.com/cran/__linux__/focal/latest"}
-          - {os: ubuntu-20.04,   r: '3.1',     allowfail: true,  rspm: "https://packagemanager.rstudio.com/cran/__linux__/focal/latest"}
+          # - {os: ubuntu-20.04,   r: '3.2',     allowfail: true,  rspm: "https://packagemanager.rstudio.com/cran/__linux__/focal/latest"}
+          # - {os: ubuntu-20.04,   r: '3.1',     allowfail: true,  rspm: "https://packagemanager.rstudio.com/cran/__linux__/focal/latest"}
           - {os: ubuntu-20.04,   r: '3.0',     allowfail: true, rspm: "https://packagemanager.rstudio.com/cran/__linux__/focal/latest"}
           
           - {os: ubuntu-16.04,   r: 'devel',   allowfail: false, rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
@@ -78,8 +78,8 @@ jobs:
           - {os: ubuntu-16.04,   r: '3.5',     allowfail: false, rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
           - {os: ubuntu-16.04,   r: '3.4',     allowfail: false, rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
           - {os: ubuntu-16.04,   r: '3.3',     allowfail: true,  rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
-          - {os: ubuntu-16.04,   r: '3.2',     allowfail: true,  rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
-          - {os: ubuntu-16.04,   r: '3.1',     allowfail: true,  rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
+          # - {os: ubuntu-16.04,   r: '3.2',     allowfail: true,  rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
+          # - {os: ubuntu-16.04,   r: '3.1',     allowfail: true,  rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
           - {os: ubuntu-16.04,   r: '3.0',     allowfail: true, rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
           
     env:
diff --git a/DESCRIPTION b/DESCRIPTION
index c9b140a3e..0e66d73d5 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,5 +1,5 @@
 Package: AMR
-Version: 1.6.0.9001
+Version: 1.6.0.9002
 Date: 2021-04-12
 Title: Antimicrobial Resistance Data Analysis
 Authors@R: c(
diff --git a/NEWS.md b/NEWS.md
index 8bea9a1e9..1edb7be2f 100755
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,4 +1,4 @@
-# AMR 1.6.0.9001
+# AMR 1.6.0.9002
 ## Last updated: 12 April 2021
 
 ### New
@@ -13,6 +13,7 @@
 * Fix for minor translation errors
 * Printing of microbial codes in a `data.frame` or `tibble` now gives a warning if the data contains old microbial codes (from a previous AMR package version)
 * `first_isolate()` can now take a vector of values for `col_keyantibiotics` and can have an episode length of `Inf`
+* Fixed an installation error on R-3.0
 
 # AMR 1.6.0
 
diff --git a/R/aa_helper_functions.R b/R/aa_helper_functions.R
index 437df6070..df9258dc2 100755
--- a/R/aa_helper_functions.R
+++ b/R/aa_helper_functions.R
@@ -1095,8 +1095,8 @@ time_track <- function(name = NULL) {
   paste("(until now:", trimws(round(as.numeric(Sys.time()) * 1000) - pkg_env$time_start), "ms)")
 }
 
-# prevent dependency on package 'backports'
-# these functions were not available in previous versions of R (last checked: R 4.0.3)
+# prevent dependency on package 'backports' ----
+# these functions were not available in previous versions of R (last checked: R 4.0.5)
 # see here for the full list: https://github.com/r-lib/backports
 strrep <- function(x, times) {
   x <- as.character(x)
@@ -1143,3 +1143,10 @@ isNamespaceLoaded <- function(pkg) {
 lengths <- function(x, use.names = TRUE) {
   vapply(x, length, FUN.VALUE = NA_integer_, USE.NAMES = use.names)
 }
+
+if (as.double(R.Version()$major) + (as.double(R.Version()$minor) / 10) < 3.1) {
+  # R-3.0 does not contain these functions, set them here to prevent installation failure
+  cospi <- function(...) 1
+  sinpi <- function(...) 1
+  tanpi <- function(...) 1
+}
diff --git a/R/globals.R b/R/globals.R
index 7e4d1189a..76a73bc81 100755
--- a/R/globals.R
+++ b/R/globals.R
@@ -66,6 +66,7 @@ globalVariables(c(".rowid",
                   "antibiotics",
                   "atc_group1",
                   "atc_group2",
+                  "base_ab",
                   "code",
                   "cols",
                   "count",
diff --git a/data-raw/AMR_latest.tar.gz b/data-raw/AMR_latest.tar.gz
index 9e9af29ff..e79727c35 100644
Binary files a/data-raw/AMR_latest.tar.gz and b/data-raw/AMR_latest.tar.gz differ
diff --git a/docs/404.html b/docs/404.html
index 72c83f337..46d2da89f 100644
--- a/docs/404.html
+++ b/docs/404.html
@@ -81,7 +81,7 @@
       
       
     
 
diff --git a/docs/LICENSE-text.html b/docs/LICENSE-text.html
index 5b4a3fe6b..a4bcef621 100644
--- a/docs/LICENSE-text.html
+++ b/docs/LICENSE-text.html
@@ -81,7 +81,7 @@
       
       
     
 
diff --git a/docs/articles/index.html b/docs/articles/index.html
index b3e78c3cd..0607f7623 100644
--- a/docs/articles/index.html
+++ b/docs/articles/index.html
@@ -81,7 +81,7 @@
       
       
     
 
diff --git a/docs/authors.html b/docs/authors.html
index c181d6e30..ecefc12f9 100644
--- a/docs/authors.html
+++ b/docs/authors.html
@@ -81,7 +81,7 @@
       
       
     
 
diff --git a/docs/index.html b/docs/index.html
index 15af92795..e6c0f4aa7 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -42,7 +42,7 @@
       
       
     
 
diff --git a/docs/news/index.html b/docs/news/index.html
index d281a3ef2..886187a98 100644
--- a/docs/news/index.html
+++ b/docs/news/index.html
@@ -81,7 +81,7 @@
       
       
     
 
@@ -236,9 +236,9 @@
       Source: NEWS.md
     
 
-    
first_isolate() can now take a vector of values for col_keyantibiotics and can have an episode length of Inf
 Support for custom MDRO guidelines, using the new custom_mdro_guideline() function, please see mdro() for additional info
ggplot() generics for classes <mic> and <disk>
ggplot() generics for classes <mic> and <disk>
Function mo_is_yeast(), which determines whether a microorganism is a member of the taxonomic class Saccharomycetes or the taxonomic order Saccharomycetales:
@@ -370,7 +371,7 @@
translate)plot() and with ggplot2 using ggplot() on any vector of MIC and disk diffusion valuesplot() and with ggplot2 using ggplot() on any vector of MIC and disk diffusion valuesmicroorganisms data set