diff --git a/NEWS.md b/NEWS.md
index 9b9885889..ee9e7bae8 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -8,6 +8,7 @@
 * Updated `estimate_infections()` so that rather than imputing missing data, it now skips these data points in the likelihood. This is a breaking change as it alters the behaviour of the model when dates are missing from a time series but are known to be zero. We recommend that users check their results when updating to this version but expect this to in most cases improve performance. By @seabbs in #528 and reviewed by @sbfnk.
 * `simulate_infections` has been renamed to `forecast_infections` in line with `simulate_secondary` and `forecast_secondary`. The terminology is: a forecast is done from a fit to existing data, a simulation from first principles. By @sbfnk in #544 and reviewed by @seabbs.
 * A new `simulate_infections` function has been added that can be used to simulate from the model from given initial conditions and parameters. By @sbfnk in #557 and reviewed by @jamesmbaazam.
+* The function `init_cumulative_fit()` has been deprecated. By @jamesmbaazam in #541 and reviewed by @sbfnk.
 
 ## Documentation
 
diff --git a/R/estimate_infections.R b/R/estimate_infections.R
index f52cee981..b678525b7 100644
--- a/R/estimate_infections.R
+++ b/R/estimate_infections.R
@@ -285,7 +285,10 @@ estimate_infections <- function(reported_cases,
 
 #' Generate initial conditions by fitting to cumulative cases
 #'
-#' @description `r lifecycle::badge("experimental")`
+#' @description `r lifecycle::badge("deprecated")`
+#'
+#' This function has been deprecated and will be removed in version 2.0.0.
+#'
 #' Fits a model to cumulative cases. This may be a useful approach to
 #' initialising a full model fit for certain data sets where the sampler gets
 #' stuck or cannot easily be initialised as fitting to cumulative cases changes
@@ -315,6 +318,11 @@ estimate_infections <- function(reported_cases,
 init_cumulative_fit <- function(args, samples = 50, warmup = 50,
                                 id = "init", verbose = FALSE,
                                 backend = "rstan") {
+  deprecate_warn(
+    when = "1.5.0",
+    what = "init_cumulative_fit()",
+    details = "The function will be removed completely in version 2.0.0."
+  )
   futile.logger::flog.debug(
     "%s: Fitting to cumulative data to initialise chains", id,
     name = "EpiNow2.epinow.estimate_infections.fit"
diff --git a/R/opts.R b/R/opts.R
index c4dae704f..f0c4db67b 100644
--- a/R/opts.R
+++ b/R/opts.R
@@ -853,13 +853,16 @@ rstan_opts <- function(object = NULL,
 #' national level fit to parametrise regional level fits. Optionally a
 #' character string can be passed with the currently supported option being
 #' "cumulative". This fits the model to cumulative cases and may be useful for
-#'  certain data sets where the sampler gets stuck or struggles to initialise.
+#' certain data sets where the sampler gets stuck or struggles to initialise.
 #' See [init_cumulative_fit()] for details.
 #'
 #' This implementation is based on the approach taken in
 #' [epidemia](https://github.com/ImperialCollegeLondon/epidemia/) authored by
 #' James Scott.
 #'
+#' This argument is deprecated and the default (NULL) will be used from
+#' version 2.0.0.
+#'
 #' @param return_fit Logical, defaults to TRUE. Should the fit stan model be
 #' returned.
 #'
@@ -915,6 +918,12 @@ stan_opts <- function(object = NULL,
     opts <- c(opts, stan_vb_opts(samples = samples, ...))
   }
   if (!is.null(init_fit)) {
+    deprecate_warn(
+      when = "1.5.0",
+      what = "stan_opts(init_fit)",
+      details = paste("This argument is deprecated and the default (NULL)",
+                      "will be used from version 2.0.0.")
+    )
     if (is.character(init_fit)) {
       init_fit <- arg_match(init_fit, values = "cumulative")
     }
diff --git a/man/init_cumulative_fit.Rd b/man/init_cumulative_fit.Rd
index adc6b2927..f0578bb92 100644
--- a/man/init_cumulative_fit.Rd
+++ b/man/init_cumulative_fit.Rd
@@ -34,7 +34,10 @@ stan models. Supported arguments are "rstan" (default) or "cmdstanr".}
 A stanfit object
 }
 \description{
-\ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#experimental}{\figure{lifecycle-experimental.svg}{options: alt='[Experimental]'}}}{\strong{[Experimental]}}
+\ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#deprecated}{\figure{lifecycle-deprecated.svg}{options: alt='[Deprecated]'}}}{\strong{[Deprecated]}}
+
+This function has been deprecated and will be removed in version 2.0.0.
+
 Fits a model to cumulative cases. This may be a useful approach to
 initialising a full model fit for certain data sets where the sampler gets
 stuck or cannot easily be initialised as fitting to cumulative cases changes
diff --git a/man/stan_opts.Rd b/man/stan_opts.Rd
index ea0ed150c..f911c089f 100644
--- a/man/stan_opts.Rd
+++ b/man/stan_opts.Rd
@@ -42,7 +42,10 @@ See \code{\link[=init_cumulative_fit]{init_cumulative_fit()}} for details.
 
 This implementation is based on the approach taken in
 \href{https://github.com/ImperialCollegeLondon/epidemia/}{epidemia} authored by
-James Scott.}
+James Scott.
+
+This argument is deprecated and the default (NULL) will be used from
+version 2.0.0.}
 
 \item{return_fit}{Logical, defaults to TRUE. Should the fit stan model be
 returned.}
diff --git a/tests/testthat/test-opts.R b/tests/testthat/test-opts.R
new file mode 100644
index 000000000..d53e5fdd4
--- /dev/null
+++ b/tests/testthat/test-opts.R
@@ -0,0 +1,3 @@
+test_that("deprecated arguments are caught", {
+  expect_deprecated(stan_opts(init_fit = "cumulative"))
+})
\ No newline at end of file