diff --git a/.dockstore.yml b/.dockstore.yml
index c0c16092a..4e49df442 100644
--- a/.dockstore.yml
+++ b/.dockstore.yml
@@ -109,6 +109,9 @@ workflows:
   - name: diff_genome_sets
     subclass: WDL
     primaryDescriptorPath: /pipes/WDL/workflows/diff_genome_sets.wdl
+  - name: download_file
+    subclass: WDL
+    primaryDescriptorPath: /pipes/WDL/workflows/download_file.wdl
   - name: downsample
     subclass: WDL
     primaryDescriptorPath: /pipes/WDL/workflows/downsample.wdl
diff --git a/pipes/WDL/tasks/tasks_assembly.wdl b/pipes/WDL/tasks/tasks_assembly.wdl
index 0df79fa70..d54a188f4 100644
--- a/pipes/WDL/tasks/tasks_assembly.wdl
+++ b/pipes/WDL/tasks/tasks_assembly.wdl
@@ -583,7 +583,7 @@ task align_reads {
     Boolean  skip_mark_dupes = false
 
     Int?     machine_mem_gb
-    String   docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String   docker = "quay.io/broadinstitute/viral-core:2.4.2"
 
     String   sample_name = basename(basename(basename(reads_unmapped_bam, ".bam"), ".taxfilt"), ".clean")
   }
@@ -849,7 +849,7 @@ task run_discordance {
       String out_basename = "run"
       Int    min_coverage = 4
 
-      String docker = "quay.io/broadinstitute/viral-core:2.4.1"
+      String docker = "quay.io/broadinstitute/viral-core:2.4.2"
     }
     parameter_meta {
       reads_aligned_bam: {
diff --git a/pipes/WDL/tasks/tasks_demux.wdl b/pipes/WDL/tasks/tasks_demux.wdl
index 2d0bbe3b4..843f2a0ac 100644
--- a/pipes/WDL/tasks/tasks_demux.wdl
+++ b/pipes/WDL/tasks/tasks_demux.wdl
@@ -6,7 +6,7 @@ task merge_tarballs {
     String       out_filename
 
     Int?         machine_mem_gb
-    String       docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String       docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
 
   Int disk_size = 2625
@@ -163,7 +163,7 @@ task illumina_demux {
 
     Int?    machine_mem_gb
     Int     disk_size = 2625
-    String  docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String  docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
 
   parameter_meta {
diff --git a/pipes/WDL/tasks/tasks_interhost.wdl b/pipes/WDL/tasks/tasks_interhost.wdl
index 043399375..a9d58f5ec 100644
--- a/pipes/WDL/tasks/tasks_interhost.wdl
+++ b/pipes/WDL/tasks/tasks_interhost.wdl
@@ -351,7 +351,7 @@ task index_ref {
     File?  novocraft_license
 
     Int?   machine_mem_gb
-    String docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
 
   Int disk_size = 100
diff --git a/pipes/WDL/tasks/tasks_ncbi.wdl b/pipes/WDL/tasks/tasks_ncbi.wdl
index 490616ffb..dded89c01 100644
--- a/pipes/WDL/tasks/tasks_ncbi.wdl
+++ b/pipes/WDL/tasks/tasks_ncbi.wdl
@@ -79,7 +79,7 @@ task sequencing_platform_from_bam {
   input {
     File    bam
 
-    String  docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String  docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
 
   command <<<
@@ -188,7 +188,7 @@ task structured_comments {
 
     File?  filter_to_ids
 
-    String docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
   String out_base = basename(assembly_stats_tsv, '.txt')
   command <<<
@@ -241,7 +241,7 @@ task structured_comments_from_aligned_bam {
     String  out_basename = basename(aligned_bam, '.bam')
     Boolean is_genome_assembly = true
     Boolean sanitize_ids = true
-    String  docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String  docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
   # see https://www.ncbi.nlm.nih.gov/genbank/structuredcomment/
   command <<<
@@ -360,7 +360,7 @@ task rename_fasta_header {
 
     String out_basename = basename(genome_fasta, ".fasta")
 
-    String docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
   command {
     set -e
@@ -525,7 +525,7 @@ task sra_meta_prep {
     Boolean     paired
 
     String      out_name = "sra_metadata.tsv"
-    String      docker="quay.io/broadinstitute/viral-core:2.4.1"
+    String      docker="quay.io/broadinstitute/viral-core:2.4.2"
   }
   Int disk_size = 100
   parameter_meta {
diff --git a/pipes/WDL/tasks/tasks_nextstrain.wdl b/pipes/WDL/tasks/tasks_nextstrain.wdl
index af2cbaef0..5f27babf8 100644
--- a/pipes/WDL/tasks/tasks_nextstrain.wdl
+++ b/pipes/WDL/tasks/tasks_nextstrain.wdl
@@ -332,7 +332,7 @@ task derived_cols {
         String?       lab_highlight_loc
         Array[File]   table_map = []
 
-        String        docker = "quay.io/broadinstitute/viral-core:2.4.1"
+        String        docker = "quay.io/broadinstitute/viral-core:2.4.2"
         Int           disk_size = 50
     }
     parameter_meta {
@@ -900,7 +900,7 @@ task filter_sequences_to_list {
 
         String       out_fname = sub(sub(basename(sequences, ".zst"), ".vcf", ".filtered.vcf"), ".fasta$", ".filtered.fasta")
         # Prior docker image: "nextstrain/base:build-20240318T173028Z"
-        String       docker = "quay.io/broadinstitute/viral-core:2.4.1"
+        String       docker = "quay.io/broadinstitute/viral-core:2.4.2"
         Int          disk_size = 750
     }
     parameter_meta {
diff --git a/pipes/WDL/tasks/tasks_read_utils.wdl b/pipes/WDL/tasks/tasks_read_utils.wdl
index b077eb572..e2603b5a6 100644
--- a/pipes/WDL/tasks/tasks_read_utils.wdl
+++ b/pipes/WDL/tasks/tasks_read_utils.wdl
@@ -84,7 +84,7 @@ task group_bams_by_sample {
 task get_bam_samplename {
   input {
     File    bam
-    String  docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String  docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
   Int   disk_size = round(size(bam, "GB")) + 50
   command <<<
@@ -111,7 +111,7 @@ task get_sample_meta {
   input {
     Array[File] samplesheets_extended
 
-    String      docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String      docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
   Int disk_size = 50
   command <<<
@@ -172,7 +172,7 @@ task merge_and_reheader_bams {
       File?        reheader_table
       String       out_basename = basename(in_bams[0], ".bam")
 
-      String       docker = "quay.io/broadinstitute/viral-core:2.4.1"
+      String       docker = "quay.io/broadinstitute/viral-core:2.4.2"
       Int          disk_size = 750
       Int          machine_mem_gb = 4
     }
@@ -244,7 +244,7 @@ task rmdup_ubam {
     String  method = "mvicuna"
 
     Int     machine_mem_gb = 7
-    String  docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String  docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
 
   Int disk_size = 375 + 2 * ceil(size(reads_unmapped_bam, "GB"))
@@ -303,7 +303,7 @@ task downsample_bams {
     Boolean      deduplicateAfter = false
 
     Int?         machine_mem_gb
-    String       docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String       docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
 
   Int disk_size = 750
@@ -370,7 +370,7 @@ task FastqToUBAM {
     Int     cpus = 2
     Int     mem_gb = 4
     Int     disk_size = 750
-    String  docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String  docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
   parameter_meta {
     fastq_1: { description: "Unaligned read1 file in fastq format", patterns: ["*.fastq", "*.fastq.gz", "*.fq", "*.fq.gz"] }
@@ -424,7 +424,7 @@ task read_depths {
     File      aligned_bam
 
     String    out_basename = basename(aligned_bam, '.bam')
-    String    docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String    docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
   Int disk_size = 200
   command <<<
diff --git a/pipes/WDL/tasks/tasks_reports.wdl b/pipes/WDL/tasks/tasks_reports.wdl
index 66de02e11..5441faac0 100644
--- a/pipes/WDL/tasks/tasks_reports.wdl
+++ b/pipes/WDL/tasks/tasks_reports.wdl
@@ -15,7 +15,7 @@ task alignment_metrics {
     Int    max_amplicons=500
 
     Int    machine_mem_gb=32
-    String docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
 
   String out_basename = basename(aligned_bam, ".bam")
@@ -142,7 +142,7 @@ task plot_coverage {
     String? plotXLimits # of the form "min max" (ints, space between)
     String? plotYLimits # of the form "min max" (ints, space between)
 
-    String  docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String  docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
 
   Int disk_size = 375
@@ -289,7 +289,7 @@ task coverage_report {
     Array[File]  mapped_bam_idx = []  # optional.. speeds it up if you provide it, otherwise we auto-index
     String       out_report_name = "coverage_report.txt"
 
-    String       docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String       docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
 
   Int disk_size = 375
@@ -364,7 +364,7 @@ task fastqc {
   input {
     File   reads_bam
 
-    String docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
   parameter_meta {
     reads_bam:{ 
@@ -412,7 +412,7 @@ task align_and_count {
     Boolean keep_duplicates_when_filtering                    = false
 
     Int?   machine_mem_gb
-    String docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
 
   String  reads_basename=basename(reads_bam, ".bam")
@@ -535,7 +535,7 @@ task align_and_count_summary {
 
     String       output_prefix = "count_summary"
 
-    String       docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String       docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
 
   Int disk_size = 100
diff --git a/pipes/WDL/tasks/tasks_taxon_filter.wdl b/pipes/WDL/tasks/tasks_taxon_filter.wdl
index 5b44654ab..fd47ff3a2 100644
--- a/pipes/WDL/tasks/tasks_taxon_filter.wdl
+++ b/pipes/WDL/tasks/tasks_taxon_filter.wdl
@@ -211,7 +211,7 @@ task merge_one_per_sample {
     Boolean      rmdup = false
 
     Int          machine_mem_gb = 7
-    String       docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String       docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
 
   Int disk_size = 750
diff --git a/pipes/WDL/tasks/tasks_terra.wdl b/pipes/WDL/tasks/tasks_terra.wdl
index 6416258eb..c7f0ee984 100644
--- a/pipes/WDL/tasks/tasks_terra.wdl
+++ b/pipes/WDL/tasks/tasks_terra.wdl
@@ -33,7 +33,7 @@ task gcs_copy {
 
 task check_terra_env {
   input {
-    String docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
   meta {
     description: "task for inspection of backend to determine whether the task is running on Terra and/or GCP"
@@ -440,7 +440,7 @@ task create_or_update_sample_tables {
     String  sample_table_name  = "sample"
     String  library_table_name = "library"
 
-    String  docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String  docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
 
   meta {
diff --git a/pipes/WDL/tasks/tasks_utils.wdl b/pipes/WDL/tasks/tasks_utils.wdl
index c2c936ecb..bee0aee82 100644
--- a/pipes/WDL/tasks/tasks_utils.wdl
+++ b/pipes/WDL/tasks/tasks_utils.wdl
@@ -52,7 +52,7 @@ task unpack_archive_to_bucket_path {
         # execution and resource requirements
         Int    disk_size      = 500
         Int    machine_mem_gb = 128
-        String docker         = "quay.io/broadinstitute/viral-core:2.4.1"
+        String docker         = "quay.io/broadinstitute/viral-core:2.4.2"
     }
 
     parameter_meta {
@@ -293,7 +293,7 @@ task zcat {
         { if [ -f /sys/fs/cgroup/memory.peak ]; then cat /sys/fs/cgroup/memory.peak; elif [ -f /sys/fs/cgroup/memory/memory.peak ]; then cat /sys/fs/cgroup/memory/memory.peak; elif [ -f /sys/fs/cgroup/memory/memory.max_usage_in_bytes ]; then cat /sys/fs/cgroup/memory/memory.max_usage_in_bytes; else echo "0"; fi } > MEM_BYTES
     >>>
     runtime {
-        docker: "quay.io/broadinstitute/viral-core:2.4.1"
+        docker: "quay.io/broadinstitute/viral-core:2.4.2"
         memory: "1 GB"
         cpu:    cpus
         disks:  "local-disk " + disk_size + " LOCAL"
@@ -367,8 +367,14 @@ task tar_extract {
 }
 
 task download_from_url {
+    # This task can be used prior to another task that consumes a file from a URL, 
+    # but where the input "protocol" is not know in advance (http[s]:// vs. gs://,drs://,etc.)
+    #
+    # After calling download_from_url, downstream tasks can then simply say:
+    #     select_first([download_from_url.downloaded_response_file, download_from_url.passthrough_url])
+    # This will allow the downstream task to consume the file since at that point it will be a bucket-local path, even if it was initially a web address.
     meta {
-        description: "Download a file from a URL. This task exists as a workaround until Terra supports this functionality natively (cromwell already does: https://cromwell.readthedocs.io/en/stable/filesystems/HTTP/). http[s] and ftp supported"
+        description: "Download a file from a URL if http[s], otherwise pass the URL through to the output. This task exists as a workaround until Terra supports http[s] inputs natively (cromwell already does: https://cromwell.readthedocs.io/en/stable/filesystems/HTTP/). http[s] and ftp supported"
         volatile: true
     }
     input {
@@ -384,11 +390,19 @@ task download_from_url {
         Boolean save_response_header_to_file = false
 
         Int     disk_size = 50
+
+        # Do not use these inputs; they are placeholders to output null values until 
+        # cromwell-on-Terra supports the null literal "None" available in WDL version >1.1
+        # see:
+        #   https://github.com/openwdl/wdl/blob/wdl-1.1/SPEC.md#optional-types-and-none
+        Int?    nullIntPlaceholder 
+        String? nullStrPlaceholder
+        File?   nullFilePlaceholder
     }
 
     parameter_meta {
       url_to_download: {
-        description: "The URL to download; this is passed to wget"
+        description: "The URL to download; this is passed to wget. If this is not an http[s] URL, the value is passed through unchanged to the 'path_str' output."      
       }
       
       output_filename: {
@@ -415,107 +429,131 @@ task download_from_url {
     }
 
     String download_subdir_local = "downloaded"
+
     command <<<
+        echo "false" > WAS_HTTP_DOWNLOAD
+
         # enforce that only one source of expected md5 hash can be provided
         ~{if defined(md5_hash_expected) && defined(md5_hash_expected_file_url) then 'echo "The inputs \'md5_hash_expected\' and \'md5_hash_expected_file_url\' cannot both be specified; please provide only one."; exit 1;' else ''}
 
-        mkdir -p "~{download_subdir_local}/tmp"
-        
-        pushd "~{download_subdir_local}"
-        
-        # ---- download desired file
-        pushd "tmp"
+        #touch SIZE_OF_DOWNLOADED_FILE_BYTES MD5_SUM_OF_DOWNLOADED_FILE
+        touch FILE_LOCATION
 
-        # if a URL-encoded version of the requested download is needed
-        #encoded_url=$(python3 -c "import urllib.parse; print urllib.parse.quote('''~{url_to_download}''')")
-        
-        # get the desired file using wget
-        # --content-disposition = use the file name suggested by the server via the Content-Disposition header
-        # --trust-server-names = ...and in the event of a redirect, use the value of the final page rather than that of the original url
-        # --save-headers = save the headers sent by the HTTP server to the file, preceding the actual contents, with an empty line as the separator.
-        wget \
-        --read-timeout 3 --waitretry 30 \
-        --no-verbose \
-        --method ~{request_method} \
-        ~{if defined(output_filename) then "--output-document ~{output_filename}" else ""} \
-        --tries ~{request_max_retries} \
-        --content-disposition --trust-server-names ~{additional_wget_opts} \
-        '~{url_to_download}' \
-        ~{if save_response_header_to_file then "--save-headers" else ""} || (echo "ERROR: request to ~{request_method} file from URL failed: ~{url_to_download}"; exit 1)
-
-        # ----
-
-        # get the name of the downloaded file
-        downloaded_file_name="$(basename "$(ls -1 | head -n1)")"
-
-        if [ ! -f "$downloaded_file_name" ]; then
-            echo "Could not locate downloaded file \"$downloaded_file_name\""
-            exit 1
-        fi
-        
-        if [ ! -s "$downloaded_file_name" ]; then
-            echo "Downloaded file appears empty: \"$downloaded_file_name\""
-            exit 1
-        fi
+        # if this is an http[s] url, download the file
+        # (otherwise just pass through the URL to the 'path_str' output)
+        if [[ ("~{url_to_download}" =~ ^(http|https|ftp):// ) ]]; then
+            mkdir -p "~{download_subdir_local}/tmp"
+            
+            pushd "~{download_subdir_local}"
+            
+            # ---- download desired file
+            pushd "tmp"
 
-        popd # return to downloaded/
+            # resolve any redirects to the final URL
+            # wget will do this automatically, but this snipped may be helpful if we ever need to output the final URL from this task
+            # resolved_url="$(curl -Ls -o /dev/null -w '%{url_effective}' '~{url_to_download}')"
+            # echo "resolved_url: ${resolved_url}"
 
-        # (only for http(s)) split http response headers from response body
-        # since wget stores both in a single file separated by a couple newlines
-        if [[ "~{url_to_download}" =~ ^https?:// ]] && ~{if save_response_header_to_file then "true" else "false"}; then
-            echo "Saving response headers separately..."
-            csplit -f response -s "tmp/${downloaded_file_name}" $'/^\r$/+1' && \
-                mv response00 "../${downloaded_file_name}.headers" && \
-                mv response01 "${downloaded_file_name}" && \
-                rm "tmp/$downloaded_file_name"
-        else
-            mv "tmp/${downloaded_file_name}" "${downloaded_file_name}"
-        fi
-        # alternative python implementation to split response headers from body
-        #   via https://stackoverflow.com/a/75483099
-        #python3 << CODE
-        #if ~{if save_response_header_to_file then "True" else "False"}:
-        #    with open("tmp/${downloaded_file_name}", "rb") as f_downloaded:
-        #        headers, body = f_downloaded.read().split(b"\r\n\r\n", 1)
-        #        # write the response header to a file
-        #        with open("${downloaded_file_name}.headers", "wb") as f_headers:
-        #            f_headers.write(headers)
-        #            f_headers.write(b"\r\n")
-        #        # save the file body to its final location
-        #        with open("${downloaded_file_name}", "wb") as f:
-        #            f.write(body)
-        #else:
-        #    ## if headers are not being saved, move the file to its final destination
-        #    import shutil
-        #    shutil.move("tmp/${downloaded_file_name}","${downloaded_file_name}")
-        #CODE
-        
-        rm -r "tmp"
+            # if a URL-encoded version of the requested download is needed
+            #encoded_url=$(python3 -c "import urllib.parse; print urllib.parse.quote('''~{url_to_download}''')")
+            
+            # get the desired file using wget
+            # --content-disposition = use the file name suggested by the server via the Content-Disposition header
+            # --trust-server-names = ...and in the event of a redirect, use the value of the final page rather than that of the original url
+            # --save-headers = save the headers sent by the HTTP server to the file, preceding the actual contents, with an empty line as the separator.
+            wget \
+            --read-timeout 3 --waitretry 30 \
+            --no-verbose \
+            --method ~{request_method} \
+            ~{if defined(output_filename) then "--output-document ~{output_filename}" else ""} \
+            --tries ~{request_max_retries} \
+            --content-disposition --trust-server-names ~{additional_wget_opts} \
+            '~{url_to_download}' \
+            ~{if save_response_header_to_file then "--save-headers" else ""} || (echo "ERROR: request to ~{request_method} file from URL failed: ~{url_to_download}"; exit 1)
+
+            # ----
+
+            # get the name of the downloaded file
+            downloaded_file_name="$(basename "$(ls -1 | head -n1)")"
+
+            if [ ! -f "$downloaded_file_name" ]; then
+                echo "Could not locate downloaded file \"$downloaded_file_name\""
+                exit 1
+            fi
+            
+            if [ ! -s "$downloaded_file_name" ]; then
+                echo "Downloaded file appears empty: \"$downloaded_file_name\""
+                exit 1
+            fi
 
-        popd # return to job working directory
+            popd # return to downloaded/
 
-        check_md5_sum() {
-            # $1 =  md5sum expected
-            # $2 =  md5sum of downloaded file
-            if [[ "$1" != "$2" ]]; then
-                echo "ERROR: md5sum of downloaded file ($2) did not match md5sum expected ($1)";
-                exit 1
+            # (only for http[s]) split http response headers from response body
+            # since wget stores both in a single file separated by a couple newlines
+            if [[ "~{url_to_download}" =~ ^https?:// ]] && ~{if save_response_header_to_file then "true" else "false"}; then
+                echo "Saving response headers separately..."
+                csplit -f response -s "tmp/${downloaded_file_name}" $'/^\r$/+1' && \
+                    mv response00 "../${downloaded_file_name}.headers" && \
+                    mv response01 "${downloaded_file_name}" && \
+                    rm "tmp/$downloaded_file_name"
+            else
+                mv "tmp/${downloaded_file_name}" "${downloaded_file_name}"
             fi
-        }
 
-        md5sum_of_downloaded=$(md5sum --binary "~{download_subdir_local}/${downloaded_file_name}" | cut -f1 -d' ' | tee MD5_SUM_OF_DOWNLOADED_FILE)
+            # alternative python implementation to split response headers from body
+            #   via https://stackoverflow.com/a/75483099
+            #python3 << CODE
+            #if ~{if save_response_header_to_file then "True" else "False"}:
+            #    with open("tmp/${downloaded_file_name}", "rb") as f_downloaded:
+            #        headers, body = f_downloaded.read().split(b"\r\n\r\n", 1)
+            #        # write the response header to a file
+            #        with open("${downloaded_file_name}.headers", "wb") as f_headers:
+            #            f_headers.write(headers)
+            #            f_headers.write(b"\r\n")
+            #        # save the file body to its final location
+            #        with open("${downloaded_file_name}", "wb") as f:
+            #            f.write(body)
+            #else:
+            #    ## if headers are not being saved, move the file to its final destination
+            #    import shutil
+            #    shutil.move("tmp/${downloaded_file_name}","${downloaded_file_name}")
+            #CODE
+            
+            rm -r "tmp"
 
-        if ~{if defined(md5_hash_expected) then 'true' else 'false'}; then
-            md5_hash_expected="~{md5_hash_expected}"
-            check_md5_sum "$md5_hash_expected" "$md5sum_of_downloaded"
-        fi
-        if ~{if defined(md5_hash_expected_file_url) then 'true' else 'false'}; then
-            md5_hash_expected="$(curl --silent ~{md5_hash_expected_file_url} | cut -f1 -d' ')"
-            check_md5_sum "$md5_hash_expected" "$md5sum_of_downloaded"
-        fi
+            popd # return to job working directory
+
+            check_md5_sum() {
+                # $1 =  md5sum expected
+                # $2 =  md5sum of downloaded file
+                if [[ "$1" != "$2" ]]; then
+                    echo "ERROR: md5sum of downloaded file ($2) did not match md5sum expected ($1)";
+                    exit 1
+                fi
+            }
 
-        # report the file size, in bytes
-        printf "Downloaded file size (bytes): " && stat --format=%s  "~{download_subdir_local}/${downloaded_file_name}" | tee SIZE_OF_DOWNLOADED_FILE_BYTES
+            md5sum_of_downloaded=$(md5sum --binary "~{download_subdir_local}/${downloaded_file_name}" | cut -f1 -d' ' | tee MD5_SUM_OF_DOWNLOADED_FILE)
+
+            if ~{if defined(md5_hash_expected) then 'true' else 'false'}; then
+                md5_hash_expected="~{md5_hash_expected}"
+                check_md5_sum "$md5_hash_expected" "$md5sum_of_downloaded"
+            fi
+            if ~{if defined(md5_hash_expected_file_url) then 'true' else 'false'}; then
+                md5_hash_expected="$(curl --silent ~{md5_hash_expected_file_url} | cut -f1 -d' ')"
+                check_md5_sum "$md5_hash_expected" "$md5sum_of_downloaded"
+            fi
+
+            # report the file size, in bytes
+            printf "Downloaded file size (bytes): " && stat --format=%s  "~{download_subdir_local}/${downloaded_file_name}" | tee SIZE_OF_DOWNLOADED_FILE_BYTES
+            echo "true" > WAS_HTTP_DOWNLOAD
+            echo "~{download_subdir_local}/${downloaded_file_name}" | tee FILE_LOCATION
+        else
+            echo "Only URLs beginning with 'http://' or 'https://' can be downloaded; passing through input url to directly to output..."
+            echo ""      > FILE_LOCATION
+            printf "0"   > SIZE_OF_DOWNLOADED_FILE_BYTES
+            printf ""    > MD5_SUM_OF_DOWNLOADED_FILE
+            echo "false" > WAS_HTTP_DOWNLOAD
+        fi
     >>>
     runtime {
         docker: "quay.io/broadinstitute/viral-baseimage:0.2.4"
@@ -527,12 +565,33 @@ task download_from_url {
         maxRetries: 0
         preemptible: 1
     }
-    output {
-        File  downloaded_response_file    = glob("downloaded/*")[0]
-        File? downloaded_response_headers = basename(downloaded_response_file) + ".headers"
 
-        Int    file_size_bytes          = read_int("SIZE_OF_DOWNLOADED_FILE_BYTES")
-        String md5_sum_of_response_file = read_string("MD5_SUM_OF_DOWNLOADED_FILE")
+    # output files
+    output {
+        # one or the other will be returned, depending on the download method
+        # an http[s] url will be downloaded to a file and available via downloaded_response_file
+        # other urls (i.e. localizable paths like 'gs://*') will be available via passthrough_url
+        # When consuming this task, select the relevant output via:
+        #   select_first([download_from_url.downloaded_response_file, download_from_url.passthrough_url])
+        #File?   downloaded_response_file_debug = read_string("FILE_LOCATION")
+        #File?   downloaded_response_file = if (read_boolean("WAS_HTTP_DOWNLOAD")) then read_string("FILE_LOCATION") else nullStrPlaceholder
+
+
+        #File?   downloaded_response_file = if (read_boolean("WAS_HTTP_DOWNLOAD")) then glob(download_subdir_local+"/*") else nullStrPlaceholder
+
+        File?   downloaded_response_file = if (read_boolean("WAS_HTTP_DOWNLOAD")) then select_first(
+                                                                                                flatten([
+                                                                                                    glob(download_subdir_local+"/*"),
+                                                                                                    ["",nullStrPlaceholder]
+                                                                                                ])
+                                                                                        ) else nullStrPlaceholder
+        String? passthrough_url          = if (read_boolean("WAS_HTTP_DOWNLOAD")) then nullStrPlaceholder else url_to_download
+
+        File?   downloaded_response_headers = if ( defined(downloaded_response_file) && save_response_header_to_file ) then basename(read_string("FILE_LOCATION")) + ".headers" else nullStrPlaceholder
+        String? md5_sum_of_response_file    = if ( defined(downloaded_response_file) ) then read_string("MD5_SUM_OF_DOWNLOADED_FILE") else nullStrPlaceholder
+        Int?    file_size_bytes             = if ( defined(downloaded_response_file) ) then floor(size(downloaded_response_file)) else nullIntPlaceholder 
+        
+        Boolean passed_through_input_url_instead_of_downloading = if ( defined(downloaded_response_file) ) then false else true
 
         File stdout = stdout()
         File stderr = stderr()
@@ -857,7 +916,7 @@ task tsv_join {
   runtime {
     memory: "~{machine_mem_gb} GB"
     cpu: 4
-    docker: "quay.io/broadinstitute/viral-core:2.4.1"
+    docker: "quay.io/broadinstitute/viral-core:2.4.2"
     disks:  "local-disk " + disk_size + " HDD"
     disk: disk_size + " GB" # TES
     dx_instance_type: "mem1_ssd1_v2_x4"
@@ -944,7 +1003,7 @@ task tsv_stack {
   input {
     Array[File]+ input_tsvs
     String       out_basename
-    String       docker = "quay.io/broadinstitute/viral-core:2.4.1"
+    String       docker = "quay.io/broadinstitute/viral-core:2.4.2"
   }
 
   Int disk_size = 50
@@ -1215,7 +1274,7 @@ task filter_sequences_by_length {
         File   sequences_fasta
         Int    min_non_N = 1
 
-        String docker = "quay.io/broadinstitute/viral-core:2.4.1"
+        String docker = "quay.io/broadinstitute/viral-core:2.4.2"
         Int    disk_size = 750
     }
     parameter_meta {
diff --git a/pipes/WDL/workflows/download_file.wdl b/pipes/WDL/workflows/download_file.wdl
new file mode 100644
index 000000000..abae32780
--- /dev/null
+++ b/pipes/WDL/workflows/download_file.wdl
@@ -0,0 +1,40 @@
+version 1.0
+
+#DX_SKIP_WORKFLOW
+
+import "../tasks/tasks_utils.wdl" as terra
+
+workflow download_file {
+    meta {
+        description: "Downloads an http[s] file. Helpful if this is not natively supported by the WDL execution backend for File inputs."
+        author: "Broad Viral Genomics"
+        email:  "viral-ngs@broadinstitute.org"
+    }
+
+    input {
+        String path_url
+    }
+
+    call terra.download_from_url {
+        input:
+            url_to_download = path_url
+    }
+
+    output {
+        File    file_path                     = select_first([download_from_url.downloaded_response_file, download_from_url.passthrough_url])
+
+        # one or the other will be returned, depending on the download method
+        # an http[s] url will be downloaded to a file and available via downloaded_response_file
+        # other urls (i.e. localizable paths like 'gs://*', 'drs://') will be available via passthrough_url
+        File?   downloaded_response_file      = download_from_url.downloaded_response_file
+        String? passthrough_url               = download_from_url.passthrough_url
+        
+        # optional fields only returned in the case of a downloaded file
+        File?   downloaded_response_headers   = download_from_url.downloaded_response_headers
+        String? md5_sum_of_response_file      = download_from_url.md5_sum_of_response_file
+        Int?    file_size_bytes               = download_from_url.file_size_bytes
+
+        # boolean flag to indicate if the download task passed through the input url instead of downloading the file
+        Boolean passed_through_input_url_instead_of_downloading  = download_from_url.passed_through_input_url_instead_of_downloading
+    }
+}
diff --git a/pipes/WDL/workflows/scaffold_and_refine_multitaxa.wdl b/pipes/WDL/workflows/scaffold_and_refine_multitaxa.wdl
index 451797522..96cbf9036 100644
--- a/pipes/WDL/workflows/scaffold_and_refine_multitaxa.wdl
+++ b/pipes/WDL/workflows/scaffold_and_refine_multitaxa.wdl
@@ -3,7 +3,9 @@ version 1.0
 import "../tasks/tasks_assembly.wdl" as assembly
 import "../tasks/tasks_ncbi.wdl" as ncbi
 import "../tasks/tasks_utils.wdl" as utils
+import "../tasks/tasks_terra.wdl" as terra
 import "assemble_refbased.wdl" as assemble_refbased
+import "download_file.wdl" as download_file
 
 workflow scaffold_and_refine_multitaxa {
     meta {
@@ -19,7 +21,8 @@ workflow scaffold_and_refine_multitaxa {
         File    reads_unmapped_bam
         File    contigs_fasta
 
-        File    taxid_to_ref_accessions_tsv
+        String  taxid_to_ref_accessions_tsv
+        String? email_address
 
         String? biosample_accession
     }
@@ -27,8 +30,21 @@ workflow scaffold_and_refine_multitaxa {
     Int    min_scaffold_unambig = 300 # in base-pairs; any scaffolded assembly < this length will not be refined/polished
     String sample_original_name = select_first([sample_name, sample_id])
 
+    call terra.check_terra_env
+
+    # get user email address, with the following precedence:
+    # 1. email_address provided via WDL input
+    # 2. user_email determined by introspection via check_terra_env task
+    # 3. (empty string fallback)
+    String user_email_address = select_first([email_address,check_terra_env.user_email, ""])
+
+    call download_file.download_file as dl_taxid_to_ref_tsv {
+        input:
+            path_url = taxid_to_ref_accessions_tsv
+    }
+
     # download (multi-segment) genomes for each reference, fasta filename = colon-concatenated accession list
-    scatter(taxon in read_tsv(taxid_to_ref_accessions_tsv)) {
+    scatter(taxon in read_tsv(dl_taxid_to_ref_tsv.file_path)) {
         # taxon = [taxid, isolate_prefix, taxname, semicolon_delim_accession_list]
         call utils.string_split {
             input:
@@ -38,7 +54,8 @@ workflow scaffold_and_refine_multitaxa {
         call ncbi.download_annotations {
             input:
                 accessions = string_split.tokens,
-                combined_out_prefix = sub(taxon[3], ":", "-")  # singularity does not like colons in filenames
+                combined_out_prefix = sub(taxon[3], ":", "-"),  # singularity does not like colons in filenames
+                emailAddress = user_email_address
         }
     }
 
@@ -72,7 +89,7 @@ workflow scaffold_and_refine_multitaxa {
         # get taxid and taxname from taxid_to_ref_accessions_tsv
         call utils.fetch_row_from_tsv as tax_lookup {
             input:
-                tsv = taxid_to_ref_accessions_tsv,
+                tsv = dl_taxid_to_ref_tsv.file_path,
                 idx_col = "accessions",
                 idx_val = sub(scaffold.scaffolding_chosen_ref_basename, "-", ":"),
                 add_header = ["taxid", "isolate_prefix", "taxname", "accessions"]
diff --git a/requirements-modules.txt b/requirements-modules.txt
index da9a876c7..1dcbe964a 100644
--- a/requirements-modules.txt
+++ b/requirements-modules.txt
@@ -1,5 +1,5 @@
 broadinstitute/viral-baseimage=0.2.4
-broadinstitute/viral-core=2.4.1
+broadinstitute/viral-core=2.4.2
 broadinstitute/viral-assemble=2.4.1.0
 broadinstitute/viral-classify=2.2.5
 broadinstitute/viral-phylo=2.4.1.0