diff --git a/.github/workflows/spark-tests.yaml b/.github/workflows/spark-tests.yaml
index b458e7c..5104a58 100644
--- a/.github/workflows/spark-tests.yaml
+++ b/.github/workflows/spark-tests.yaml
@@ -31,6 +31,11 @@ jobs:
     steps:
       - uses: actions/checkout@v3
 
+      - uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: '17'
+
       - uses: r-lib/actions/setup-r@v2
         with:
           r-version: 'release'
diff --git a/.github/workflows/test-coverage.yaml b/.github/workflows/test-coverage.yaml
index c031bf3..b19f44c 100644
--- a/.github/workflows/test-coverage.yaml
+++ b/.github/workflows/test-coverage.yaml
@@ -16,7 +16,7 @@ jobs:
       fail-fast: false
       matrix:
         config:
-          - {spark: '4.0.1', pyspark: '4.0.1', hadoop: '3', scala: '2.13', python: '3.10', name: 'PySpark 4'}
+          - {spark: '4.1.1', pyspark: '4.1.1', hadoop: '3', scala: '2.13', python: '3.13', name: 'PySpark 4'}
 
     env:
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
@@ -31,6 +31,11 @@ jobs:
     steps:
       - uses: actions/checkout@v3
 
+      - uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: '21'
+
       - uses: r-lib/actions/setup-r@v2
         with:
           r-version: 'release'
@@ -45,8 +50,14 @@ jobs:
             any::tidymodels
             any::probably
             any::rpart
+            any::pak
           needs: check
 
+      - name: Install sparklyr dev
+        run: |
+          pak::pak("sparklyr/sparklyr")
+        shell: Rscript {0}
+
       - name: Cache Spark
         id: cache-spark
         uses: actions/cache@v3
diff --git a/R/python-to-pandas-cleaned.R b/R/python-to-pandas-cleaned.R
index cf6747b..ae8d948 100644
--- a/R/python-to-pandas-cleaned.R
+++ b/R/python-to-pandas-cleaned.R
@@ -23,10 +23,22 @@ to_pandas_cleaned <- function(x) {
   } else {
     # Pandas 3.0 conversion makes encases all columns inside lists
     collected <- try(
-      pandas_tbl$values |>
-        as.data.frame() |>
-        lapply(unlist) |>
-        set_names(x$columns),
+      {
+        as.data.frame(pandas_tbl$values) |>
+          lapply(\(col) {
+            map_vec(
+              col,
+              \(x) {
+                if (length(x) == 0 || is.nan(x)) {
+                  NA
+                } else {
+                  x[[1]]
+                }
+              }
+            )
+          }) |>
+          set_names(x$columns)
+      },
       silent = TRUE
     )
     if (inherits(collected, "try-error")) {
@@ -35,6 +47,42 @@ to_pandas_cleaned <- function(x) {
     }
   }
 
+  # Handle NULL columns by converting them to appropriate empty vectors
+  for (i in seq_along(collected)) {
+    if (is.null(collected[[i]])) {
+      collected[[i]] <- character(0)
+    }
+    # Convert arrow_binary to list
+    if (inherits(collected[[i]], "arrow_binary")) {
+      collected[[i]] <- as.list(collected[[i]])
+    }
+    # Convert UTC timestamps to local timezone
+    if (inherits(collected[[i]], "POSIXct")) {
+      # If the timestamp is in UTC, convert to local timezone
+      if (!is.null(attr(collected[[i]], "tzone")) && attr(collected[[i]], "tzone") == "UTC") {
+        attr(collected[[i]], "tzone") <- ""
+      }
+    }
+    # Convert pandas Arrow-backed arrays to regular R vectors
+    if (inherits(collected[[i]], "python.builtin.object")) {
+      col_class <- try(class(collected[[i]]), silent = TRUE)
+      if (!inherits(col_class, "try-error")) {
+        # Check if it's an Arrow-backed array from pandas
+        if (any(grepl("ArrowStringArray|ArrowExtensionArray", col_class))) {
+          # Convert to regular character vector using numpy
+          collected[[i]] <- try(
+            as.character(collected[[i]]$to_numpy()),
+            silent = TRUE
+          )
+          # Fallback to Python list conversion if to_numpy fails
+          if (inherits(collected[[i]], "try-error")) {
+            collected[[i]] <- as.character(collected[[i]]$tolist())
+          }
+        }
+      }
+    }
+  }
+
   collected <- collected |>
     dplyr::as_tibble()
 
@@ -64,11 +112,16 @@ to_pandas_cleaned <- function(x) {
         as.Date(map_vec(col, clean_col), origin = "1970-01-01")
       } else if (py_type == "date" && r_type == "character") {
         as.Date(col, origin = "1970-01-01")
+      } else if (py_type == "date" && r_type %in% c("numeric", "integer", "logical")) {
+        as.Date(col, origin = "1970-01-01")
       } else if (py_type == "boolean" && r_type == "list") {
         map_lgl(col, clean_col)
       } else if (py_type == "boolean" && r_type == "character") {
         as.logical(col)
-      } else if (r_type == "numeric") {
+      } else if (r_type == "integer" && py_type %in% c("bigint", "long")) {
+        # Convert bigint/long to numeric since R integer is 32-bit
+        as.numeric(col)
+      } else if (r_type == "numeric" || r_type == "integer") {
         if (py_type %in% c("tinyint", "smallint", "int")) {
           ptype <- integer()
         } else {
diff --git a/R/start-stop-service.R b/R/start-stop-service.R
index 7e49a9c..4771e88 100644
--- a/R/start-stop-service.R
+++ b/R/start-stop-service.R
@@ -74,12 +74,32 @@ spark_connect_service_start <- function(
     }
   )
 
-  output <- prs$read_all_output()
-  cli_bullets(c(" " = "{.info {output}}"))
-  error <- prs$read_all_error()
-  if (error != "") {
-    cli_abort(error)
+  # Wait briefly to see if there's immediate output or errors
+  # Don't use read_all_output() as it blocks until process closes stdout
+  # Spark Connect is a long-running service, so we only check initial output
+  prs$poll_io(timeout = 2000)  # Wait max 2 seconds
+
+  # Read only what's available, don't wait for EOF
+  if (prs$is_alive()) {
+    output <- prs$read_output_lines()
+    if (length(output) > 0) {
+      cli_bullets(c(" " = "{.info {paste(output, collapse = '\n')}}"))
+    }
+    error <- prs$read_error_lines()
+    if (length(error) > 0 && any(nzchar(error))) {
+      cli_alert_warning(paste(error, collapse = "\n"))
+    }
+  } else {
+    # Process exited immediately, likely an error
+    if (prs$get_exit_status() != 0) {
+      error <- prs$read_all_error()
+      cli_abort(c("Failed to start Spark Connect service", "x" = error))
+    }
   }
+
+  # Store the process for potential cleanup
+  assign("spark_connect_process", prs, envir = .GlobalEnv)
+
   cli_end()
   invisible()
 }
@@ -97,6 +117,17 @@ spark_connect_service_stop <- function(version = "4.0", ...) {
     stderr = "|",
     stdin = "|"
   )
+
+  # Wait for shutdown command to complete
+  prs$wait(timeout = 5000)  # Wait max 5 seconds
+
   cli_bullets(c(" " = "{.info - Shutdown command sent}"))
+
+  # Clean up stored process reference
+  if (exists("spark_connect_process", envir = .GlobalEnv)) {
+    rm("spark_connect_process", envir = .GlobalEnv)
+  }
+
   cli_end()
+  invisible()
 }
diff --git a/R/tune-grid.R b/R/tune-grid.R
index 1f47c07..838bb6c 100644
--- a/R/tune-grid.R
+++ b/R/tune-grid.R
@@ -1,3 +1,17 @@
+# Helper to get tune functions that may have dots in dev version
+tune_fn <- function(name) {
+  # Dev tune exports with dot prefix, CRAN tune without
+  dot_name <- paste0(".", name)
+  ns <- asNamespace("tune")
+  if (exists(dot_name, where = ns)) {
+    getFromNamespace(dot_name, "tune")
+  } else if (exists(name, where = ns)) {
+    getFromNamespace(name, "tune")
+  } else {
+    stop("Function '", name, "' not found in tune package")
+  }
+}
+
 #' @importFrom sparklyr tune_grid_spark
 #' @export
 tune_grid_spark.pyspark_connection <- function(
@@ -57,7 +71,7 @@ tune_grid_spark.pyspark_connection <- function(
   # section
   vec_resamples <- resamples |>
     vctrs::vec_split(by = 1:nrow(resamples)) |>
-    _$val
+    (\(x) x$val)()
   pasted_pkgs <- paste0("'", prepped$needed_pkgs, "'", collapse = ", ")
 
   # --------------- Prepares and uploads R objects to Spark --------------------
@@ -78,18 +92,35 @@ tune_grid_spark.pyspark_connection <- function(
   }
   spark_session_add_file(vec_resamples, sc, hash_resamples)
 
+  # ------------------- Upload tune internal functions -------------------------
+  # For Spark 4.1.1+ with Python 3.13, internal functions don't serialize properly
+  # Capture them here and upload as an RDS file
+  # Use tune_fn() to handle both dev (with dot) and CRAN (without dot) versions
+  tune_fns <- list(
+    get_data_subsets = tune_fn("get_data_subsets"),
+    loop_over_all_stages = tune_fn("loop_over_all_stages")
+  )
+  hash_tune_fns <- "tune_fns"
+  spark_session_add_file(tune_fns, sc, hash_tune_fns)
+
   # -------------------------- Creates the UDF ---------------------------------
   # Uses the `loop_call` function as the base of the UDF that will be sent to
   # the Spark session. It works by modifying the text of the function, specifically
   # the file names it reads to load the different R object components
+
+  # Inject function loading code for Spark 4.1.1+ compatibility
+  # This will be inserted at the top of loop_call and will load tune functions
+  function_capture_code <- "library(tidymodels)"
+
   grid_code <- loop_call |>
     deparse() |>
     paste0(collapse = "\n") |>
     str_replace("\"rsample\"", pasted_pkgs) |>
     str_replace("debug <- TRUE", "debug <- FALSE") |>
-    str_replace("xy <- 1", "library(tidymodels)") |>
+    str_replace("xy <- 1", function_capture_code) |>
     str_replace("static.rds", path(hash_static, ext = "rds")) |>
-    str_replace("resamples.rds", path(hash_resamples, ext = "rds"))
+    str_replace("resamples.rds", path(hash_resamples, ext = "rds")) |>
+    str_replace("tune_fns.rds", path(hash_tune_fns, ext = "rds"))
 
   # -------------------- Creates and uploads the grid  -------------------------
   res_id_df <- purrr::map_df(
@@ -307,23 +338,47 @@ loop_call <- function(x) {
     stop("Packages ", missing_pkgs, " are missing")
   }
   xy <- 1
+
   # ------------------- Reads files with needed R objects ----------------------
   # Loads the needed R objects from disk
   debug <- TRUE
   static_fname <- "static.rds"
   resample_fname <- "resamples.rds"
+  tune_fns_fname <- "tune_fns.rds"
   if (isFALSE(debug)) {
     pyspark <- reticulate::import("pyspark")
     static_file <- pyspark$SparkFiles$get(static_fname)
     resample_file <- pyspark$SparkFiles$get(resample_fname)
+    tune_fns_file <- pyspark$SparkFiles$get(tune_fns_fname)
   } else {
     temp_path <- Sys.getenv("TEMP_SPARK_GRID", unset = "~")
     static_file <- file.path(temp_path, static_fname)
     resample_file <- file.path(temp_path, resample_fname)
+    tune_fns_file <- file.path(temp_path, tune_fns_fname)
   }
   static <- readRDS(static_file)
   resamples <- readRDS(resample_file)
 
+  # Load tune internal functions (or use fallback for direct test calls)
+  if (file.exists(tune_fns_file)) {
+    tune_fns <- readRDS(tune_fns_file)
+    get_data_subsets <- tune_fns$get_data_subsets
+    loop_over_all_stages <- tune_fns$loop_over_all_stages
+  } else {
+    # Fallback for direct calls in tests (debug mode without uploaded file)
+    # Try both naming conventions (dev uses dots, CRAN doesn't)
+    tryCatch({
+      get_data_subsets <- getFromNamespace(".get_data_subsets", "tune")
+    }, error = function(e) {
+      get_data_subsets <<- getFromNamespace("get_data_subsets", "tune")
+    })
+    tryCatch({
+      loop_over_all_stages <- getFromNamespace(".loop_over_all_stages", "tune")
+    }, error = function(e) {
+      loop_over_all_stages <<- getFromNamespace("loop_over_all_stages", "tune")
+    })
+  }
+
   # ------------ Iterates through all the combinations in `x` ------------------
   # Spark will more likely send more than one row (combination) in `x`. It
   # will depend on how the grid data frame was partitioned inside Spark.
@@ -340,7 +395,7 @@ loop_call <- function(x) {
     index <- curr_x$index
     curr_resample <- resamples[[index]]
 
-    data_splits <- tune:::get_data_subsets(
+    data_splits <- get_data_subsets(
       static$wflow,
       curr_resample$splits[[1]],
       static$split_args
@@ -351,13 +406,8 @@ loop_call <- function(x) {
     curr_grid <- tibble::as_tibble(curr_grid)
     assign(".Random.seed", c(1L, 2L, 3L), envir = .GlobalEnv)
     # ------ Sends current combination to `tune` for processing ----------------
-    # TODO: This function check exists because the `tune` version in the Spark
-    # cluster may be CRAN. This needs to be removed by the time of release
-    if (exists(".loop_over_all_stages", where = "package:tune")) {
-      res <- tune::.loop_over_all_stages(curr_resample, curr_grid, static)
-    } else {
-      res <- tune:::loop_over_all_stages(curr_resample, curr_grid, static)
-    }
+    # Use the captured function to ensure it's available in Spark workers
+    res <- loop_over_all_stages(curr_resample, curr_grid, static)
     # -------------------- Extracts metrics from results -----------------------
     # Mapping function accepts only tables as output, so only the metrics are
     # being sent back instead of the entire results object
@@ -451,7 +501,7 @@ prep_static <- function(
     data = resamples$splits[[1]]$data,
     grid_names = names(grid)
   )
-  grid <- tune::.check_grid(
+  grid <- tune_fn("check_grid")(
     grid = grid,
     workflow = wf,
     pset = param_info
@@ -475,7 +525,7 @@ prep_static <- function(
       control_err
     ))
   }
-  control <- tune::.update_parallel_over(control, resamples, grid)
+  control <- tune_fn("update_parallel_over")(control, resamples, grid)
   eval_time <- tune::check_eval_time_arg(eval_time, wf_metrics, call = call)
   needed_pkgs <- c(
     "rsample",
@@ -495,11 +545,11 @@ prep_static <- function(
   out$static <- list(
     wflow = wf,
     param_info = param_info,
-    configs = tune::.get_config_key(grid, wf),
+    configs = tune_fn("get_config_key")(grid, wf),
     post_estimation = workflows::.workflow_postprocessor_requires_fit(wf),
     metrics = wf_metrics,
     metric_info = tibble::as_tibble(wf_metrics),
-    pred_types = tune::.determine_pred_types(wf, wf_metrics),
+    pred_types = tune_fn("determine_pred_types")(wf, wf_metrics),
     eval_time = eval_time,
     split_args = rsample::.get_split_args(resamples),
     control = control,
diff --git a/tests/testthat.R b/tests/testthat.R
index 85e89fc..00aad07 100644
--- a/tests/testthat.R
+++ b/tests/testthat.R
@@ -7,7 +7,7 @@
 # * https://testthat.r-lib.org/articles/special-files.html
 
 # Sys.setenv("CODE_COVERAGE" = "true")
-# Sys.setenv("SPARK_VERSION" = "4.0.1"); Sys.setenv("SCALA_VERSION" = "2.13"); Sys.setenv("PYTHON_VERSION" = "3.10")
+# Sys.setenv("SPARK_VERSION" = "4.1.1"); Sys.setenv("SCALA_VERSION" = "2.13"); Sys.setenv("PYTHON_VERSION" = "3.13")
 # Sys.setenv("SPARK_VERSION" = "3.5.7"); Sys.setenv("SCALA_VERSION" = "2.12"); Sys.setenv("PYTHON_VERSION" = "3.10")
 if (identical(Sys.getenv("CODE_COVERAGE"), "true")) {
   library(testthat)
diff --git a/tests/testthat/_snaps/ml-feature-transformers.md b/tests/testthat/_snaps/ml-feature-transformers.md
index dba7be8..aa161f4 100644
--- a/tests/testthat/_snaps/ml-feature-transformers.md
+++ b/tests/testthat/_snaps/ml-feature-transformers.md
@@ -611,6 +611,7 @@
       dplyr::pull(ft_ngram(ft_tokenizer(use_test_table_reviews(), "x", "token_x"),
       "token_x", "ngram_x"))
     Output
+      <list<character>[1]>
       [[1]]
        [1] "this has"      "has been"      "been the"      "the best"     
        [5] "best tv"       "tv i've"       "i've ever"     "ever used."   
@@ -888,6 +889,7 @@
     Code
       dplyr::pull(ft_regex_tokenizer(use_test_table_reviews(), "x", "new_x"))
     Output
+      <list<character>[1]>
       [[1]]
        [1] "this"    "has"     "been"    "the"     "best"    "tv"      "i've"   
        [8] "ever"    "used."   "great"   "screen," "and"     "sound." 
@@ -1063,6 +1065,7 @@
       dplyr::pull(ft_stop_words_remover(ft_tokenizer(use_test_table_reviews(),
       input_col = "x", output_col = "token_x"), input_col = "token_x", output_col = "stop_x"))
     Output
+      <list<character>[1]>
       [[1]]
       [1] "best"    "tv"      "ever"    "used."   "great"   "screen," "sound." 
       
@@ -1114,6 +1117,7 @@
     Code
       dplyr::pull(ft_tokenizer(use_test_table_reviews(), input_col = "x", output_col = "token_x"))
     Output
+      <list<character>[1]>
       [[1]]
        [1] "this"    "has"     "been"    "the"     "best"    "tv"      "i've"   
        [8] "ever"    "used."   "great"   "screen," "and"     "sound." 
diff --git a/tests/testthat/helper-init.R b/tests/testthat/helper-init.R
index 9059abb..b359707 100644
--- a/tests/testthat/helper-init.R
+++ b/tests/testthat/helper-init.R
@@ -59,6 +59,7 @@ use_test_connect_start <- function() {
     cli_inform("SCALA_VERSION: {use_test_scala_spark()}")
     cli_inform("PYTHON_VERSION: {use_test_python_version()}")
     cli_h2("")
+    print(reticulate::py_list_packages())
 
     withr::with_envvar(
       new = c(
diff --git a/tests/testthat/helper-ml.R b/tests/testthat/helper-ml.R
index ab3e5fc..a70fa10 100644
--- a/tests/testthat/helper-ml.R
+++ b/tests/testthat/helper-ml.R
@@ -3,6 +3,23 @@ use_test_pull <- function(x, table = FALSE) {
   if (table) {
     x <- table(x)
   }
+
+  # Handle Spark ML vectors that come through as structured data frames
+  # (Spark 4.1+ with Pandas 3.0+ converts ML vectors to data frames with type, size, indices, values columns)
+  if (is.data.frame(x) && all(c("type", "size", "indices", "values") %in% names(x))) {
+    # Extract the values column which contains the actual vector data
+    x <- data.frame(
+      x = map_chr(x$values, function(vec) {
+        if (is.null(vec) || length(vec) == 0) {
+          ""
+        } else {
+          paste(as.vector(vec), collapse = ", ")
+        }
+      })
+    )
+    return(x)
+  }
+
   if (inherits(x[[1]], "array")) {
     x <- as.double(map(x, as.vector))
   }
@@ -16,6 +33,13 @@ use_test_pull <- function(x, table = FALSE) {
       x = map_chr(x, function(x) paste(as.vector(x$array), collapse = ", "))
     )
   }
+  # Handle vectors that have been converted to numeric during pandas conversion
+  # (Spark 4.1+ with Pandas 3.0+ converts ML vectors to numeric vectors)
+  if (is.list(x) && length(x) > 0 && is.numeric(x[[1]]) && !is.data.frame(x)) {
+    x <- data.frame(
+      x = map_chr(x, function(vec) paste(as.vector(vec), collapse = ", "))
+    )
+  }
   x
 }
 
diff --git a/tests/testthat/setup.R b/tests/testthat/setup.R
index 020ac7c..8f5b57c 100644
--- a/tests/testthat/setup.R
+++ b/tests/testthat/setup.R
@@ -3,11 +3,22 @@ suppressPackageStartupMessages(library(sparklyr))
 suppressPackageStartupMessages(library(cli))
 
 ## Clean up at end
-# withr::defer({
-# Disconnecting from Spark
-# withr::defer(spark_disconnect_all(), teardown_env())
-# Stopping Spark Connect service
-# withr::defer(pysparklyr::spark_connect_service_stop("4.0.1"))
-# Deleting main Python environment
-# withr::defer(fs::dir_delete(use_test_env()), teardown_env())
-# })
+withr::defer({
+  # Disconnecting from Spark
+  try(spark_disconnect_all(), silent = TRUE)
+
+  # Stopping Spark Connect service
+  try(spark_connect_service_stop(use_test_version_spark()), silent = TRUE)
+
+  # Kill process if still running
+  if (exists("spark_connect_process", envir = .GlobalEnv)) {
+    prs <- get("spark_connect_process", envir = .GlobalEnv)
+    if (prs$is_alive()) {
+      try(prs$kill(), silent = TRUE)
+    }
+    rm("spark_connect_process", envir = .GlobalEnv)
+  }
+
+  # Deleting main Python environment (commented out as it may be too aggressive)
+  # try(fs::dir_delete(use_test_env()), silent = TRUE)
+}, testthat::teardown_env())