diff --git a/.buildlibrary b/.buildlibrary
index b57220b..1257866 100644
--- a/.buildlibrary
+++ b/.buildlibrary
@@ -1,4 +1,4 @@
-ValidationKey: '10057500'
+ValidationKey: '12069600'
 AutocreateReadme: yes
 AcceptedWarnings:
 - 'Warning: package ''.*'' was built under R version'
diff --git a/CITATION.cff b/CITATION.cff
index f3e8686..c6b5b6e 100644
--- a/CITATION.cff
+++ b/CITATION.cff
@@ -2,8 +2,8 @@ cff-version: 1.2.0
 message: If you use this software, please cite it using the metadata from this file.
 type: software
 title: 'mrdrivers: Create GDP and Population Scenarios'
-version: 5.0.0
-date-released: '2025-01-27'
+version: 6.0.0
+date-released: '2025-01-28'
 abstract: Create GDP and population scenarios This package constructs the GDP and
   population scenarios used as drivers in both the REMIND and MAgPIE models.
 authors:
diff --git a/DESCRIPTION b/DESCRIPTION
index 23d5ae0..e241edf 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: mrdrivers
 Type: Package
 Title: Create GDP and Population Scenarios
-Version: 5.0.0
+Version: 6.0.0
 Authors@R: c(person(given = "Johannes", 
                     family = "Koch", 
                     email = "jokoch@pik-potsdam.de", 
@@ -44,6 +44,6 @@ Suggests:
 Encoding: UTF-8
 Roxygen: list(markdown = TRUE)
 RoxygenNote: 7.3.2
-Date: 2025-01-27
+Date: 2025-01-28
 Config/testthat/edition: 3
 VignetteBuilder: knitr
diff --git a/R/calcRatioPPP2MER.R b/R/calcRatioPPP2MER.R
deleted file mode 100644
index 0f4f5d1..0000000
--- a/R/calcRatioPPP2MER.R
+++ /dev/null
@@ -1,31 +0,0 @@
-#' MER over PPP ratio
-#'
-#' Get a conversion factor to convert GDP in constant 2017 Int$PPP into constant 2017 US$MER.
-#' Use the "when" argument to switch the year of the conversion factor. Source = WDI. Countries with missing data are
-#' filled in with 1. Regional aggregation is weighed by GDP from WDI-MI in the year set by "when".
-#'
-#' @param when An integer (defaults to 2017) specifying the year of the PPP2MER factor.
-#' @inherit madrat::calcOutput return
-#' @seealso [madrat::calcOutput()]
-#' @examples \dontrun{
-#' calcOutput("RatioPPP2MER")
-#' }
-#'
-calcRatioPPP2MER <- function(when = 2017) {
-
-  data <- readSource("WDI", "PA.NUS.PPPC.RF")[, when, ]
-  # Replace 0s with 1s. This was done previously. Other solutions here should be taken into consideration.
-  data[data == 0] <- 1
-  # Set names and years to NULL, for GAMS interface to work.
-  getNames(data) <- NULL
-  getYears(data) <- NULL
-
-  weight <- calcOutput("GDPPast", aggregate = FALSE, years = when)
-
-  list(x = data,
-       weight = weight,
-       unit = glue::glue("constant {when} US$MER / constant {when} Int$PPP"),
-       description = glue::glue("Ratio of GDP in constant {when} US$MER over GDP in constant {when} Int$PPP (source: \\
-                                WDI). Can be used to convert between GDP at constant {when} Int$PPP and GDP at \\
-                                constant {when} US$MER."))
-}
diff --git a/README.md b/README.md
index 4b7622e..ce36a9a 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # Create GDP and Population Scenarios
 
-R package **mrdrivers**, version **5.0.0**
+R package **mrdrivers**, version **6.0.0**
 
 [![CRAN status](https://www.r-pkg.org/badges/version/mrdrivers)](https://cran.r-project.org/package=mrdrivers) [![R build status](https://pik-piam.github.io/mrdrivers/workflows/check/badge.svg)](https://pik-piam.github.io/mrdrivers/actions) [![codecov](https://codecov.io/gh/mrdrivers/branch/master/graph/badge.svg)](https://app.codecov.io/gh/mrdrivers) [![r-universe](https://pik-piam.r-universe.dev/badges/mrdrivers)](https://pik-piam.r-universe.dev/builds)
 
@@ -100,7 +100,7 @@ In case of questions / problems please contact Johannes Koch <jokoch@pik-potsdam
 
 To cite package **mrdrivers** in publications use:
 
-Koch J, Soergel B, Leip D, Benke F, Dietrich J (2025). "mrdrivers: Create GDP and Population Scenarios." Version: 5.0.0, <https://pik-piam.github.io/mrdrivershttps://github.com/pik-piam/mrdrivers>.
+Koch J, Soergel B, Leip D, Benke F, Dietrich J (2025). "mrdrivers: Create GDP and Population Scenarios." Version: 6.0.0, <https://pik-piam.github.io/mrdrivershttps://github.com/pik-piam/mrdrivers>.
 
 A BibTeX entry for LaTeX users is
 
@@ -108,10 +108,10 @@ A BibTeX entry for LaTeX users is
 @Misc{,
   title = {mrdrivers: Create GDP and Population Scenarios},
   author = {Johannes Koch and Bjoern Soergel and Deborra Leip and Falk Benke and Jan Philipp Dietrich},
-  date = {2025-01-27},
+  date = {2025-01-28},
   year = {2025},
   url = {https://pik-piam.github.io/mrdrivers},
   url = {https://github.com/pik-piam/mrdrivers},
-  note = {Version: 5.0.0},
+  note = {Version: 6.0.0},
 }
 ```
diff --git a/man/calcRatioPPP2MER.Rd b/man/calcRatioPPP2MER.Rd
deleted file mode 100644
index 3b19ac6..0000000
--- a/man/calcRatioPPP2MER.Rd
+++ /dev/null
@@ -1,30 +0,0 @@
-% Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/calcRatioPPP2MER.R
-\name{calcRatioPPP2MER}
-\alias{calcRatioPPP2MER}
-\title{MER over PPP ratio}
-\usage{
-calcRatioPPP2MER(when = 2017)
-}
-\arguments{
-\item{when}{An integer (defaults to 2017) specifying the year of the PPP2MER factor.}
-}
-\value{
-magpie object with the requested output data either on country or on
-regional level depending on the choice of argument "aggregate" or a list of information
-if supplementary is set to TRUE.
-}
-\description{
-Get a conversion factor to convert GDP in constant 2017 Int$PPP into constant 2017 US$MER.
-Use the "when" argument to switch the year of the conversion factor. Source = WDI. Countries with missing data are
-filled in with 1. Regional aggregation is weighed by GDP from WDI-MI in the year set by "when".
-}
-\examples{
-\dontrun{
-calcOutput("RatioPPP2MER")
-}
-
-}
-\seealso{
-\code{\link[madrat:calcOutput]{madrat::calcOutput()}}
-}
diff --git a/tests/testthat/test-03-calcOutput_sets.R b/tests/testthat/test-03-calcOutput_sets.R
index 1f6576e..f9302db 100644
--- a/tests/testthat/test-03-calcOutput_sets.R
+++ b/tests/testthat/test-03-calcOutput_sets.R
@@ -29,7 +29,6 @@ test_that("set names", {
   expectCorrectSetNames(calcOutput("GDPpcFuture"))
   expectCorrectSetNames(calcOutput("GDP", extension2150 = "none"))
   expectCorrectSetNames(calcOutput("GDPpc", extension2150 = "none"))
-  # Want to keep:  expectCorrectSetNames(calcOutput("RatioPPP2MER"))
 })
 
 
@@ -184,22 +183,3 @@ test_that("GDPpc factored by its weight is equal to GDP, in MER", {
   comment(y) <- NULL
   expect_equal(x, y)
 })
-
-test_that("ppp2mer is consistent with GDP in PPP and MER", {
-  gdp1 <- calcOutput("GDP", unit = "constant 2017 US$MER", aggregate = FALSE)
-  gdp2 <- calcOutput("GDP", unit = "constant 2017 Int$PPP", aggregate = FALSE)
-  ppp2merDef <- calcOutput("RatioPPP2MER", aggregate = FALSE)
-
-  diff <- gdp1 / gdp2 - ppp2merDef
-
-  expect_lt(max(diff), 1e-12)
-
-  # On regional level
-  gdp1 <- calcOutput("GDP", unit = "constant 2017 US$MER")
-  gdp2 <- calcOutput("GDP", unit = "constant 2017 Int$PPP")
-  ppp2merDef <- calcOutput("RatioPPP2MER")
-
-  diff <- gdp1 / gdp2 - ppp2merDef
-
-  expect_lt(max(diff[, 2020, ]), 1e-2)
-})
diff --git a/tests/testthat/test-09-snaphsots.R b/tests/testthat/test-09-snaphsots.R
index 4e572d3..26fe024 100644
--- a/tests/testthat/test-09-snaphsots.R
+++ b/tests/testthat/test-09-snaphsots.R
@@ -37,7 +37,3 @@ test_that("Default calcOutput Urban calls", {
 test_that("Default calcOutput Labour calls", {
   expect_snapshot_value(fh(calcOutput("Labour")), style = "json2")
 })
-
-test_that("Default calcOutput RatioPPP2MER call", {
-  expect_snapshot_value(calcOutput("RatioPPP2MER"), style = "json2")
-})