diff --git a/README.md b/README.md
index 6b6f143..ef1b40b 100644
--- a/README.md
+++ b/README.md
@@ -213,12 +213,13 @@ When contributing to this library, it is therefore important to ensure that all
 
 We are currently on major release v4.  Breaking changes should be marked with the [deprecated](https://www.doxygen.nl/manual/commands.html#cmddeprecated) doxygen tag.  The following changes are planned when the next major/breaking release (v5) becomes necessary:
 
-* mf_getuniquelibref.sas to have the deprecated maxtried parameter removed (no longer needed)
-* mp_testservice.sas to be renamed as mp_execute.sas (as it doesn't actually test anything)
-* `insert_cmplib` option of mcf_xxx macros will be deprecated (the option is now checked automatically with value inserted only if needed)
+* mcf_xxx macros to have `insert_cmplib` option deprecated (the option is now checked automatically with value inserted only if needed)
 * mcf_xxx macros to have `wrap=` option defaulted to YES for convenience.  Set this option explicitly to avoid issues.
-* mp_getddl.sas to be renamed to mp_ds2ddl.sas (consistent with other ds2xxx macros).  A wrapper macro is already in place, and you are able to use this immediately.  The default for SHOWLOG will also be YES instead of NO.
+* mf_getuniquelibref.sas to have the deprecated maxtries parameter removed (no longer needed)
+* mp_abort.sas will have the redundant type= parameter removed.
 * mp_coretable.sas will be replaced by the standalone macros in the `ddl` folder (which are already available)
+* mp_getddl.sas to be renamed to mp_ds2ddl.sas (consistent with other ds2xxx macros).  A wrapper macro is already in place, and you are able to use this immediately.  The default for SHOWLOG will also be YES instead of NO.
+* mp_testservice.sas to be renamed as mp_execute.sas (as it doesn't actually test anything)
 
 ## Star Gazing
 
diff --git a/all.sas b/all.sas
index e2532e6..7a0a9c5 100644
--- a/all.sas
+++ b/all.sas
@@ -4002,10 +4002,6 @@ run;
   ignorelist=,
   outds=work.test_results
 )/*/STORE SOURCE*/;
-%local ds test_result test_comments del add mod ilist;
-%let ilist=%upcase(&sasjs_prefix._FUNCTIONS SYS_PROCHTTP_STATUS_CODE
-  SYS_PROCHTTP_STATUS_CODE SYS_PROCHTTP_STATUS_PHRASE &ignorelist);
-
 /**
   * this sets up the global vars, it will also enter STRICT mode.  If this
   * behaviour is not desired, simply initiate the following global macro
@@ -4013,6 +4009,10 @@ run;
   */
 %mp_init()
 
+%local ds test_result test_comments del add mod ilist;
+%let ilist=%upcase(&sasjs_prefix._FUNCTIONS SYS_PROCHTTP_STATUS_CODE
+  SYS_PROCHTTP_STATUS_CODE SYS_PROCHTTP_STATUS_PHRASE &ignorelist);
+
 /* get current variables */
 %if &action=SNAPSHOT %then %do;
   proc sql;
@@ -24355,6 +24355,7 @@ run;
   @li mp_base64copy.sas
   @li mp_replace.sas
   @li mv_createfolder.sas
+  @li mv_getviyafileextparms.sas
 
   <h4> Related Macros</h4>
   @li mv_createfile.sas
@@ -24439,7 +24440,7 @@ run;
 
 options noquotelenmax;
 %local base_uri; /* location of rest apis */
-%let base_uri=%mf_getplatform(VIYARESTAPI);
+%let base_uri=%trim(%mf_getplatform(VIYARESTAPI));
 
 /* create folder if it does not already exist */
 %local folderds self_uri;
@@ -24458,7 +24459,7 @@ run;
 /* abort or delete if file already exists */
 %let force=%upcase(&force);
 %local fileuri ;
-%let fileuri=%mfv_getpathuri(&path/&name);
+%let fileuri=%trim(%mfv_getpathuri(&path/&name));
 %mp_abort(iftrue=(%mf_isblank(&fileuri)=0 and &force ne YES)
   ,mac=MV_CREATEFILE
   ,msg=%str(File &path/&name already exists and force=&force)
@@ -24485,7 +24486,13 @@ run;
 
 %local url mimetype ext;
 %let url=&base_uri/files/files?parentFolderUri=&self_uri;
-%let ext=%upcase(%scan(&name,-1,.));
+%let ext=%upcase(%trim(%scan(&name,-1,.)));
+
+/* Get Viya file-extension details into some macro variables */
+%mv_getViyaFileExtParms(&ext
+                        ,propertiesVar=viyaProperties
+                        ,typeDefNameVar=viyaTypeDefName
+                        ,mdebug=&mdebug);
 
 /* fetch job info */
 %local fname1;
@@ -24498,12 +24505,23 @@ proc http method='POST' out=&fname1 &oauth_bearer in=&fref
   %else %do;
     ct="&ctype"
   %end;
-  %if "&ext"="HTML" or "&ext"="CSS" or "&ext"="JS" or "&ext"="PNG"
-  or "&ext"="SVG" %then %do;
-    url="&url%str(&)typeDefName=file";
+
+  /* typeDefName */
+  %if not %mf_isBlank(&viyaTypeDefName) %then %do;
+    url="&url%str(&)typeDefName=&viyaTypeDefName";
   %end;
   %else %do;
-    url="&url";
+    %if "&ext"="HTM" or "&ext"="HTML" or "&ext"="XHTML" %then %do;
+      url="&url%str(&)typeDefName=file_html";
+    %end;
+    %else %do;
+      %if "&ext"="CSS" or "&ext"="JS" or "&ext"="PNG" or "&ext"="SVG" %then %do;
+        url="&url%str(&)typeDefName=file_%lowcase(&ext)";
+      %end;
+      %else %do;
+        url="&url";
+      %end;
+    %end;
   %end;
 
   headers "Accept"="application/json"
@@ -24525,6 +24543,7 @@ run;
   ,mac=MV_CREATEFILE
   ,msg=%str(&SYS_PROCHTTP_STATUS_CODE &SYS_PROCHTTP_STATUS_PHRASE)
 )
+
 %local libref2;
 %let libref2=%mf_getuniquelibref();
 libname &libref2 JSON fileref=&fname1;
@@ -24532,12 +24551,60 @@ libname &libref2 JSON fileref=&fname1;
 data &outds;
   set &libref2..links end=last;
   if rel='createChild' then do;
-    call symputx('href',quote(cats("&base_uri",href)),'l');
     &dbg put (_all_)(=);
   end;
 run;
 
-%put &sysmacroname: %trim(&base_uri)%mfv_getpathuri(&path/&name);
+/* URI of the created file */
+%let fileuri=%trim(%mfv_getpathuri(&path/&name));
+
+/* If properties were found then patch the file to include them */
+%if not %mf_isBlank(%superq(viyaProperties)) %then %do;
+  /* Wrap the properties object in a root object also containing the file name */
+  %local viyapatch;
+  %let viyapatch = %sysfunc(pathname(work))/%mf_getuniquename(prefix=patch_json_);
+  data _null_;
+    length line $32767;
+    file "&viyapatch" lrecl=32767;
+    put '{ "name": "' "&name" '",';
+    line = cat('"properties": ',symget("viyaProperties"));
+    put line;
+    put '}';
+    stop;
+  run;
+
+  %if &mdebug=1 %then %do;
+    data _null_;
+      if (_n_ eq 1) then put 'DEBUG: ** PATCH JSON **';
+      infile "&viyapatch" end=last;
+      input;
+      put _infile_;
+    run;
+  %end;
+
+  /* And apply the properties to the newly created file, using the PATCH method */
+  %let fref=%mf_getuniquefileref();
+  filename &fref "&viyapatch";
+  %let url=&base_uri&fileuri;
+
+  proc http method='PATCH' oauth_bearer=sas_services in=&fref
+    url="&url";
+    headers "Accept"="application/json"
+            "Content-Type"="application/json"
+            "If-Match"="*";
+    %if &mdebug=1 %then %do;
+      debug level=2;
+    %end;
+  run;
+  %if &mdebug=1 %then %put &sysmacroname PATCH &=url
+    &=SYS_PROCHTTP_STATUS_CODE &=SYS_PROCHTTP_STATUS_PHRASE;
+  %mp_abort(iftrue=(&SYS_PROCHTTP_STATUS_CODE ne 200)
+    ,mac=MV_CREATEFILE
+    ,msg=%str(&SYS_PROCHTTP_STATUS_CODE &SYS_PROCHTTP_STATUS_PHRASE)
+  )
+%end;
+
+%put &sysmacroname: &base_uri&fileuri;
 %put /SASJobExecution?_file=&path/&name;%put;
 
 %if &mdebug=0 %then %do;
@@ -28111,6 +28178,252 @@ filename &fname1 clear;
 libname &libref1 clear;
 
 %mend mv_getusers;/**
+  @file mv_getviyafileextparms.sas
+  @brief Reads the VIYA file-extension type definition and returns selected
+    values in SAS macro variables
+
+  @details Content is derived from the following endpoint:
+    "https://${serverUrl}/types/types?limit=999999"
+
+  @param [in] ext File extension to retrieve property info for.
+  @param [out] propertiesVar= SAS macro variable name that will contain
+    the 'properties' object json, if found, else blank.
+  @param [out] typeDefNameVar= SAS macro variable name that will contain
+    the 'typeDefName' property value, if found, else blank.
+  @param [out] mediaTypeVar= SAS macro variable name that will contain
+    the 'mediaType' property value, if found, else blank.
+  @param [out] viyaFileExtRespLibDs (work.mv_getViyaFileExtParmsResponse)
+    Library.name of the dataset to receive the local working copy of the initial
+    response that requests all file extension details. Created once per session
+    to avoid multiple api calls.
+  @param [in] mdebug= (0) Set to 1 to enable DEBUG messages
+
+  <h4> SAS Macros </h4>
+  @li mf_existds.sas
+  @li mf_getplatform.sas
+  @li mf_getuniquefileref.sas
+  @li mf_getuniquename.sas
+  @li mf_getvalue.sas
+  @li mf_getvarlist.sas
+  @li mf_getvartype.sas
+  @li mf_nobs.sas
+  @li mp_abort.sas
+
+*/
+
+%macro mv_getViyaFileExtParms(
+  ext,
+  typeDefNameVar=,
+  propertiesVar=,
+  mediaTypeVar=,
+  viyaFileExtRespLibDs=work.mv_getViyaFileExtParmsResponse,
+  mdebug=0
+  );
+  %local base_uri; /* location of rest apis */
+  %local url; /* File extension info end-point */
+
+  %mp_abort(
+    iftrue=(%mf_isBlank(&ext))
+    ,msg=%str(No file extension provided.)
+    ,mac=MV_GETVIYAFILEEXTPARMS
+  );
+
+  %mp_abort(
+    iftrue=(%mf_isBlank(&typeDefNameVar) and
+            %mf_isBlank(&propertiesVar) and
+            %mf_isBlank(&mediaTypeVar))
+    ,msg=%str(MV_GETVIYAFILEEXTPARMS - No parameter was requested.)
+    ,mac=MV_GETVIYAFILEEXTPARMS
+  );
+
+  %mp_abort(
+    iftrue=(%mf_isBlank(&viyaFileExtRespLibDs))
+    ,msg=%str(No <libname.>dataset name provided to cache inital response.)
+    ,mac=MV_GETVIYAFILEEXTPARMS
+  );
+
+  /* Declare requested parameters as global macro vars and initialize blank */
+  %if not %mf_isBlank(&typeDefNameVar) %then %do;
+    %global &typeDefNameVar;
+    %let &typeDefNameVar = %str();
+  %end;
+  %if not %mf_isBlank(&propertiesVar) %then %do;
+    %global &propertiesVar;
+    %let &propertiesVar = %str();
+  %end;
+  %if not %mf_isBlank(&mediaTypeVar) %then %do;
+    %global &mediaTypeVar;
+    %let &mediaTypeVar = %str();
+  %end;
+
+  %let base_uri=%mf_getplatform(VIYARESTAPI);
+  %if &mdebug=1 %then %do;
+    %put DEBUG: &=base_uri;
+  %end;
+
+  %let ext=%lowcase(&ext);
+
+  /* Create a local copy of the Viya response containing all file type info, if
+  it does not already exist. */
+  %if not %mf_existds(&viyaFileExtRespLibDs) %then %do;
+    /* Create a temp file and fill with JSON that declares */
+    /* VIYA file-type details for the given file extension */
+    %local viyatypedefs;
+    %let viyatypedefs=%mf_getuniquefileref();
+    filename &viyatypedefs temp;
+
+    %let url = &base_uri/types/types?limit=999999;
+
+    proc http oauth_bearer=sas_services out=&viyatypedefs
+      url="&url";
+    run;
+
+    %if &mdebug=1 %then %put DEBUG: &sysmacroname &=url
+      &=SYS_PROCHTTP_STATUS_CODE &=SYS_PROCHTTP_STATUS_PHRASE;
+
+    %if (&SYS_PROCHTTP_STATUS_CODE ne 200) %then %do;
+      /* To avoid a breaking change, exit early if the request failed.
+        The calling process will proceed with empty requested macro variables. */
+      %put INFO: &sysmacroname File extension details were not retrieved.;
+      filename &viyatypedefs clear;
+      %return;
+    %end;
+
+    %if &mdebug=1 %then %do;
+      /* Dump the response to the log */
+      data _null_;
+        length line $120;
+        null=byte(0);
+        infile &viyatypedefs dlm=null lrecl=120 recfm=n;
+        input line $120.;
+        if _n_ = 1 then put "DEBUG:";
+        put line;
+      run;
+    %end;
+
+    /* Convert the content of that JSON into SAS datasets */
+      /* First prepare a new WORK-based folder to receive the datasets */
+    %local jsonworkfolder jsonlib opt_dlcreatedir;
+    %let jsonworkfolder=%sysfunc(pathname(work))/%mf_getuniquename(prefix=json_);
+    %let jsonlib=%mf_getuniquelibref(prefix=json);
+      /* And point a libname at it */
+    %let opt_dlcreatedir = %sysfunc(getoption(dlcreatedir));
+    options dlcreatedir; libname &jsonlib "&jsonworkfolder"; options &opt_dlcreatedir;
+
+    /* Read the json output once and copy datasets to its work folder */
+    %local libref1;
+    %let libref1=%mf_getuniquelibref();
+    libname &libref1 JSON fileref=&viyatypedefs automap=create;
+    proc copy in=&libref1 out=&jsonlib; run;
+
+    libname &libref1 clear;
+
+    /* Now give all rows belonging to the same items array a grouping value */
+    data &viyaFileExtRespLibDs;
+      length _viyaItemIdx 8;
+      set &jsonlib..alldata;
+      retain _viyaItemIdx 0;
+      /* Increment the row group index when a new 'items' group is observed */
+      if P=1 and P1='items' then _viyaItemIdx + 1;
+    run;
+
+    %if &mdebug=0 %then %do;
+      /* Tidy up, unless debug=1 */
+      proc datasets library=&jsonlib nolist kill; quit;
+      libname &jsonlib clear;
+    %end;
+
+    filename &viyatypedefs clear;
+
+  %end; /* If initial filetype query response didn't exist */
+
+  /* Find the row-group for the current file extension */
+  %local itemRowGroup;
+  %let itemRowGroup =
+    %mf_getValue(
+      &viyaFileExtRespLibDs
+      ,_viyaItemIdx
+      ,filter=%quote(p1='items' and p2='extensions' and value="&ext")
+    );
+
+  %if &mdebug %then %put DEBUG: &=itemRowGroup;
+
+  %if %mf_isBlank(&itemRowGroup) %then %do;
+    /* extension was not found */
+    %if(&mdebug=1) %then %put DEBUG: No type details found for extension "&ext".;
+    %return;
+  %end;
+
+  /* Filter the cached response data down to the required file extension */
+  %local dsItems;
+  %let dsItems = %mf_getuniquename(prefix=dsItems_);
+  data work.&dsItems;
+    set &viyaFileExtRespLibDs;
+    where _viyaItemIdx = &itemRowGroup;
+  run;
+
+  /* Populate typeDefName, if requested */
+  %if (not %mf_isBlank(&typeDefNameVar)) %then %do;
+    %let &typeDefNameVar = %mf_getvalue(&dsItems,value,filter=%quote(p1="items" and p2="name"));
+    %if &mdebug=1 %then %put DEBUG: &=typeDefNameVar &typeDefNameVar=&&&typeDefNameVar;
+  %end;
+
+  /* Populate mediaType, if requested */
+  %if (not %mf_isBlank(&mediaTypeVar)) %then %do;
+    %let &mediaTypeVar = %mf_getvalue(&dsItems,value,filter=%quote(p1="items" and p2="mediaType"));
+    %if &mdebug=1 %then %put DEBUG: &=mediaTypeVar &mediaTypeVar=&&&mediaTypeVar;
+  %end;
+
+  /* Populate properties macro variable, if requested */
+  %if not %mf_isBlank(&propertiesVar) %then %do;
+
+    /* Filter dsItems down to the properties */
+    %local dsProperties;
+    %let dsProperties = %mf_getuniquename(prefix=dsProperties_);
+    data work.&dsProperties ( rename=(p3 = propertyName) );
+        set work.&dsItems;
+        where p2="properties" and v=1;
+    run;
+
+    /* Check for 1+ properties */
+    %if ( %mf_nobs(&dsProperties) = 0 ) %then %do;
+      %let &propertiesVar = %str();
+      %if &mdebug=1 %then %put DEBUG: &SYSMACRONAME - No Viya properties found for file suffix %str(%')&ext%str(%');
+    %end;
+    %else %do;
+      /* Properties potentially span multiple rows in the input table */
+      data _null_;
+        length
+          line $32767
+          properties $32767
+        ;
+        retain properties;
+        set &dsProperties end=last;
+        if _n_ = 1 then properties = '{';
+
+        line = cats(quote(trim(propertyName)),':');
+        /* Only strings and bools appear in properties */
+        if value not in ("true","false") then value = quote(trim(value));
+        line = catx(' ',line,value);
+        /* Add a comma separator to all except the last line */
+        if not last then line = cats(line,',');
+
+        /* Add this line to the output value */
+        properties = catx(' ',properties,line);
+
+        if last then do;
+          /* Close off the properties object and output to the macro variable */
+          properties=catx(' ',properties,'}');
+          call symputx("&propertiesVar",properties);
+        end;
+      run;
+
+      %if &mdebug=1 %then %put DEBUG: &=propertiesVar &propertiesVar=&&&propertiesVar;
+    %end;
+
+  %end;
+
+%mend mv_getViyaFileExtParms;/**
   @file
   @brief Executes a SAS Viya Job
   @details Triggers a SAS Viya Job, with optional URL parameters, using
diff --git a/base/mp_assertscope.sas b/base/mp_assertscope.sas
index f1dfc70..213b146 100644
--- a/base/mp_assertscope.sas
+++ b/base/mp_assertscope.sas
@@ -73,10 +73,6 @@
   ignorelist=,
   outds=work.test_results
 )/*/STORE SOURCE*/;
-%local ds test_result test_comments del add mod ilist;
-%let ilist=%upcase(&sasjs_prefix._FUNCTIONS SYS_PROCHTTP_STATUS_CODE
-  SYS_PROCHTTP_STATUS_CODE SYS_PROCHTTP_STATUS_PHRASE &ignorelist);
-
 /**
   * this sets up the global vars, it will also enter STRICT mode.  If this
   * behaviour is not desired, simply initiate the following global macro
@@ -84,6 +80,10 @@
   */
 %mp_init()
 
+%local ds test_result test_comments del add mod ilist;
+%let ilist=%upcase(&sasjs_prefix._FUNCTIONS SYS_PROCHTTP_STATUS_CODE
+  SYS_PROCHTTP_STATUS_CODE SYS_PROCHTTP_STATUS_PHRASE &ignorelist);
+
 /* get current variables */
 %if &action=SNAPSHOT %then %do;
   proc sql;
diff --git a/tests/viyaonly/mv_getviyafileextparms.test.sas b/tests/viyaonly/mv_getviyafileextparms.test.sas
new file mode 100644
index 0000000..2aa665a
--- /dev/null
+++ b/tests/viyaonly/mv_getviyafileextparms.test.sas
@@ -0,0 +1,96 @@
+/**
+  @file
+  @brief Testing mv_getviyafileextparms macro
+
+  <h4> SAS Macros </h4>
+  @li mf_isBlank.sas
+  @li mp_assert.sas
+  @li mp_assertscope.sas
+  @li mv_getviyafileextparms.sas
+
+**/
+
+options mprint;
+
+%let mvarIgnoreList =
+  MC0_JADP1LEN MC0_JADP2LEN MC0_JADP3LEN MC0_JADPNUM MC0_JADVLEN
+  SASJSPROCESSMODE SASJS_STPSRV_HEADER_LOC;
+
+%put TEST 1 - Test with common extension, requesting only typeDefName parameter;
+%mp_assertscope(SNAPSHOT)
+%mv_getviyafileextparms(ext=txt, typeDefNameVar=viyaTypeDefName)
+%mp_assertscope(COMPARE
+  ,ignorelist=&mvarIgnoreList viyaTypeDefName
+)
+
+%mp_assert(
+  iftrue=(not %mf_isBlank(&viyaTypeDefName)),
+  desc=Check the requested macro variable viyaTypeDefName is not blank.
+)
+
+%put TEST 2 - Test with common extension, requesting only properties parameter;
+%mp_assertscope(SNAPSHOT)
+%mv_getviyafileextparms(ext=html, propertiesVar=viyaProperties)
+%mp_assertscope(COMPARE
+  ,ignorelist=&mvarIgnoreList viyaProperties
+)
+
+%mp_assert(
+  iftrue=(not %mf_isBlank(%superq(viyaProperties))),
+  desc=Check the requested macro variable viyaProperties is not blank.
+)
+
+%put TEST 3 - Test with common extension, requesting only mediaType parameter;
+%mp_assertscope(SNAPSHOT)
+%mv_getviyafileextparms(ext=mp3, mediaTypeVar=viyaMediaType)
+%mp_assertscope(COMPARE
+  ,ignorelist=&mvarIgnoreList viyaMediaType
+)
+
+%mp_assert(
+  iftrue=(not %mf_isBlank(&viyaMediaType)),
+  desc=Check the requested macro variable viyaMediaType is not blank.
+)
+
+%put TEST 4 - Test with common extension, requesting all parameters;
+%mp_assertscope(SNAPSHOT)
+%mv_getviyafileextparms(
+  ext=css,
+  typeDefNameVar=cssViyaTypeDefName,
+  propertiesVar=cssViyaProperties,
+  mediaTypeVar=cssViyaMediaType
+  )
+%mp_assertscope(COMPARE
+  ,ignorelist=
+    &mvarIgnoreList cssViyaTypeDefName cssViyaProperties  cssViyaMediaType
+)
+
+%mp_assert(
+  iftrue=(not ( %mf_isBlank(&cssViyaTypeDefName) or
+                %mf_isBlank(%superq(cssViyaProperties)) or
+                %mf_isBlank(&cssViyaMediaType) ) ),
+  desc=Check a full set of requested macro variables are not blank.
+)
+
+
+%put TEST 5 - Test with invalid extension - requested parameters will be blank;
+%mp_assertscope(SNAPSHOT)
+%mv_getviyafileextparms(
+  ext=xxxINVALIDxxx,
+  typeDefNameVar=invalidTypeDefName,
+  propertiesVar=invalidProperties,
+  mediaTypeVar=invalidMediaType
+  )
+%mp_assertscope(COMPARE
+  ,ignorelist=
+    &mvarIgnoreList invalidTypeDefName invalidProperties invalidMediaType
+)
+
+%mp_assert(
+  iftrue=(
+    %mf_isBlank(&invalidTypeDefName) and
+    %mf_isBlank(%superq(invalidProperties)) and
+    %mf_isBlank(&invalidMediaType)
+    ),
+  desc=Check the requested macro variables are all blank.
+)
diff --git a/viya/mv_createfile.sas b/viya/mv_createfile.sas
index 1c00e28..6778910 100644
--- a/viya/mv_createfile.sas
+++ b/viya/mv_createfile.sas
@@ -69,6 +69,7 @@
   @li mp_base64copy.sas
   @li mp_replace.sas
   @li mv_createfolder.sas
+  @li mv_getviyafileextparms.sas
 
   <h4> Related Macros</h4>
   @li mv_createfile.sas
@@ -153,7 +154,7 @@
 
 options noquotelenmax;
 %local base_uri; /* location of rest apis */
-%let base_uri=%mf_getplatform(VIYARESTAPI);
+%let base_uri=%trim(%mf_getplatform(VIYARESTAPI));
 
 /* create folder if it does not already exist */
 %local folderds self_uri;
@@ -172,7 +173,7 @@ run;
 /* abort or delete if file already exists */
 %let force=%upcase(&force);
 %local fileuri ;
-%let fileuri=%mfv_getpathuri(&path/&name);
+%let fileuri=%trim(%mfv_getpathuri(&path/&name));
 %mp_abort(iftrue=(%mf_isblank(&fileuri)=0 and &force ne YES)
   ,mac=MV_CREATEFILE
   ,msg=%str(File &path/&name already exists and force=&force)
@@ -199,7 +200,13 @@ run;
 
 %local url mimetype ext;
 %let url=&base_uri/files/files?parentFolderUri=&self_uri;
-%let ext=%upcase(%scan(&name,-1,.));
+%let ext=%upcase(%trim(%scan(&name,-1,.)));
+
+/* Get Viya file-extension details into some macro variables */
+%mv_getViyaFileExtParms(&ext
+                        ,propertiesVar=viyaProperties
+                        ,typeDefNameVar=viyaTypeDefName
+                        ,mdebug=&mdebug);
 
 /* fetch job info */
 %local fname1;
@@ -212,12 +219,23 @@ proc http method='POST' out=&fname1 &oauth_bearer in=&fref
   %else %do;
     ct="&ctype"
   %end;
-  %if "&ext"="HTML" or "&ext"="CSS" or "&ext"="JS" or "&ext"="PNG"
-  or "&ext"="SVG" %then %do;
-    url="&url%str(&)typeDefName=file";
+
+  /* typeDefName */
+  %if not %mf_isBlank(&viyaTypeDefName) %then %do;
+    url="&url%str(&)typeDefName=&viyaTypeDefName";
   %end;
   %else %do;
-    url="&url";
+    %if "&ext"="HTM" or "&ext"="HTML" or "&ext"="XHTML" %then %do;
+      url="&url%str(&)typeDefName=file_html";
+    %end;
+    %else %do;
+      %if "&ext"="CSS" or "&ext"="JS" or "&ext"="PNG" or "&ext"="SVG" %then %do;
+        url="&url%str(&)typeDefName=file_%lowcase(&ext)";
+      %end;
+      %else %do;
+        url="&url";
+      %end;
+    %end;
   %end;
 
   headers "Accept"="application/json"
@@ -239,6 +257,7 @@ run;
   ,mac=MV_CREATEFILE
   ,msg=%str(&SYS_PROCHTTP_STATUS_CODE &SYS_PROCHTTP_STATUS_PHRASE)
 )
+
 %local libref2;
 %let libref2=%mf_getuniquelibref();
 libname &libref2 JSON fileref=&fname1;
@@ -246,12 +265,60 @@ libname &libref2 JSON fileref=&fname1;
 data &outds;
   set &libref2..links end=last;
   if rel='createChild' then do;
-    call symputx('href',quote(cats("&base_uri",href)),'l');
     &dbg put (_all_)(=);
   end;
 run;
 
-%put &sysmacroname: %trim(&base_uri)%mfv_getpathuri(&path/&name);
+/* URI of the created file */
+%let fileuri=%trim(%mfv_getpathuri(&path/&name));
+
+/* If properties were found then patch the file to include them */
+%if not %mf_isBlank(%superq(viyaProperties)) %then %do;
+  /* Wrap the properties object in a root object also containing the file name */
+  %local viyapatch;
+  %let viyapatch = %sysfunc(pathname(work))/%mf_getuniquename(prefix=patch_json_);
+  data _null_;
+    length line $32767;
+    file "&viyapatch" lrecl=32767;
+    put '{ "name": "' "&name" '",';
+    line = cat('"properties": ',symget("viyaProperties"));
+    put line;
+    put '}';
+    stop;
+  run;
+
+  %if &mdebug=1 %then %do;
+    data _null_;
+      if (_n_ eq 1) then put 'DEBUG: ** PATCH JSON **';
+      infile "&viyapatch" end=last;
+      input;
+      put _infile_;
+    run;
+  %end;
+
+  /* And apply the properties to the newly created file, using the PATCH method */
+  %let fref=%mf_getuniquefileref();
+  filename &fref "&viyapatch";
+  %let url=&base_uri&fileuri;
+
+  proc http method='PATCH' oauth_bearer=sas_services in=&fref
+    url="&url";
+    headers "Accept"="application/json"
+            "Content-Type"="application/json"
+            "If-Match"="*";
+    %if &mdebug=1 %then %do;
+      debug level=2;
+    %end;
+  run;
+  %if &mdebug=1 %then %put &sysmacroname PATCH &=url
+    &=SYS_PROCHTTP_STATUS_CODE &=SYS_PROCHTTP_STATUS_PHRASE;
+  %mp_abort(iftrue=(&SYS_PROCHTTP_STATUS_CODE ne 200)
+    ,mac=MV_CREATEFILE
+    ,msg=%str(&SYS_PROCHTTP_STATUS_CODE &SYS_PROCHTTP_STATUS_PHRASE)
+  )
+%end;
+
+%put &sysmacroname: &base_uri&fileuri;
 %put /SASJobExecution?_file=&path/&name;%put;
 
 %if &mdebug=0 %then %do;
diff --git a/viya/mv_getviyafileextparms.sas b/viya/mv_getviyafileextparms.sas
new file mode 100644
index 0000000..50baa38
--- /dev/null
+++ b/viya/mv_getviyafileextparms.sas
@@ -0,0 +1,247 @@
+/**
+  @file mv_getviyafileextparms.sas
+  @brief Reads the VIYA file-extension type definition and returns selected
+    values in SAS macro variables
+
+  @details Content is derived from the following endpoint:
+    "https://${serverUrl}/types/types?limit=999999"
+
+  @param [in] ext File extension to retrieve property info for.
+  @param [out] propertiesVar= SAS macro variable name that will contain
+    the 'properties' object json, if found, else blank.
+  @param [out] typeDefNameVar= SAS macro variable name that will contain
+    the 'typeDefName' property value, if found, else blank.
+  @param [out] mediaTypeVar= SAS macro variable name that will contain
+    the 'mediaType' property value, if found, else blank.
+  @param [out] viyaFileExtRespLibDs (work.mv_getViyaFileExtParmsResponse)
+    Library.name of the dataset to receive the local working copy of the initial
+    response that requests all file extension details. Created once per session
+    to avoid multiple api calls.
+  @param [in] mdebug= (0) Set to 1 to enable DEBUG messages
+
+  <h4> SAS Macros </h4>
+  @li mf_existds.sas
+  @li mf_getplatform.sas
+  @li mf_getuniquefileref.sas
+  @li mf_getuniquename.sas
+  @li mf_getvalue.sas
+  @li mf_getvarlist.sas
+  @li mf_getvartype.sas
+  @li mf_nobs.sas
+  @li mp_abort.sas
+
+*/
+
+%macro mv_getViyaFileExtParms(
+  ext,
+  typeDefNameVar=,
+  propertiesVar=,
+  mediaTypeVar=,
+  viyaFileExtRespLibDs=work.mv_getViyaFileExtParmsResponse,
+  mdebug=0
+  );
+  %local base_uri; /* location of rest apis */
+  %local url; /* File extension info end-point */
+
+  %mp_abort(
+    iftrue=(%mf_isBlank(&ext))
+    ,msg=%str(No file extension provided.)
+    ,mac=MV_GETVIYAFILEEXTPARMS
+  );
+
+  %mp_abort(
+    iftrue=(%mf_isBlank(&typeDefNameVar) and
+            %mf_isBlank(&propertiesVar) and
+            %mf_isBlank(&mediaTypeVar))
+    ,msg=%str(MV_GETVIYAFILEEXTPARMS - No parameter was requested.)
+    ,mac=MV_GETVIYAFILEEXTPARMS
+  );
+
+  %mp_abort(
+    iftrue=(%mf_isBlank(&viyaFileExtRespLibDs))
+    ,msg=%str(No <libname.>dataset name provided to cache inital response.)
+    ,mac=MV_GETVIYAFILEEXTPARMS
+  );
+
+  /* Declare requested parameters as global macro vars and initialize blank */
+  %if not %mf_isBlank(&typeDefNameVar) %then %do;
+    %global &typeDefNameVar;
+    %let &typeDefNameVar = %str();
+  %end;
+  %if not %mf_isBlank(&propertiesVar) %then %do;
+    %global &propertiesVar;
+    %let &propertiesVar = %str();
+  %end;
+  %if not %mf_isBlank(&mediaTypeVar) %then %do;
+    %global &mediaTypeVar;
+    %let &mediaTypeVar = %str();
+  %end;
+
+  %let base_uri=%mf_getplatform(VIYARESTAPI);
+  %if &mdebug=1 %then %do;
+    %put DEBUG: &=base_uri;
+  %end;
+
+  %let ext=%lowcase(&ext);
+
+  /* Create a local copy of the Viya response containing all file type info, if
+  it does not already exist. */
+  %if not %mf_existds(&viyaFileExtRespLibDs) %then %do;
+    /* Create a temp file and fill with JSON that declares */
+    /* VIYA file-type details for the given file extension */
+    %local viyatypedefs;
+    %let viyatypedefs=%mf_getuniquefileref();
+    filename &viyatypedefs temp;
+
+    %let url = &base_uri/types/types?limit=999999;
+
+    proc http oauth_bearer=sas_services out=&viyatypedefs
+      url="&url";
+    run;
+
+    %if &mdebug=1 %then %put DEBUG: &sysmacroname &=url
+      &=SYS_PROCHTTP_STATUS_CODE &=SYS_PROCHTTP_STATUS_PHRASE;
+
+    %if (&SYS_PROCHTTP_STATUS_CODE ne 200) %then %do;
+      /* To avoid a breaking change, exit early if the request failed.
+        The calling process will proceed with empty requested macro variables. */
+      %put INFO: &sysmacroname File extension details were not retrieved.;
+      filename &viyatypedefs clear;
+      %return;
+    %end;
+
+    %if &mdebug=1 %then %do;
+      /* Dump the response to the log */
+      data _null_;
+        length line $120;
+        null=byte(0);
+        infile &viyatypedefs dlm=null lrecl=120 recfm=n;
+        input line $120.;
+        if _n_ = 1 then put "DEBUG:";
+        put line;
+      run;
+    %end;
+
+    /* Convert the content of that JSON into SAS datasets */
+      /* First prepare a new WORK-based folder to receive the datasets */
+    %local jsonworkfolder jsonlib opt_dlcreatedir;
+    %let jsonworkfolder=%sysfunc(pathname(work))/%mf_getuniquename(prefix=json_);
+    %let jsonlib=%mf_getuniquelibref(prefix=json);
+      /* And point a libname at it */
+    %let opt_dlcreatedir = %sysfunc(getoption(dlcreatedir));
+    options dlcreatedir; libname &jsonlib "&jsonworkfolder"; options &opt_dlcreatedir;
+
+    /* Read the json output once and copy datasets to its work folder */
+    %local libref1;
+    %let libref1=%mf_getuniquelibref();
+    libname &libref1 JSON fileref=&viyatypedefs automap=create;
+    proc copy in=&libref1 out=&jsonlib; run;
+
+    libname &libref1 clear;
+
+    /* Now give all rows belonging to the same items array a grouping value */
+    data &viyaFileExtRespLibDs;
+      length _viyaItemIdx 8;
+      set &jsonlib..alldata;
+      retain _viyaItemIdx 0;
+      /* Increment the row group index when a new 'items' group is observed */
+      if P=1 and P1='items' then _viyaItemIdx + 1;
+    run;
+
+    %if &mdebug=0 %then %do;
+      /* Tidy up, unless debug=1 */
+      proc datasets library=&jsonlib nolist kill; quit;
+      libname &jsonlib clear;
+    %end;
+
+    filename &viyatypedefs clear;
+
+  %end; /* If initial filetype query response didn't exist */
+
+  /* Find the row-group for the current file extension */
+  %local itemRowGroup;
+  %let itemRowGroup =
+    %mf_getValue(
+      &viyaFileExtRespLibDs
+      ,_viyaItemIdx
+      ,filter=%quote(p1='items' and p2='extensions' and value="&ext")
+    );
+
+  %if &mdebug %then %put DEBUG: &=itemRowGroup;
+
+  %if %mf_isBlank(&itemRowGroup) %then %do;
+    /* extension was not found */
+    %if(&mdebug=1) %then %put DEBUG: No type details found for extension "&ext".;
+    %return;
+  %end;
+
+  /* Filter the cached response data down to the required file extension */
+  %local dsItems;
+  %let dsItems = %mf_getuniquename(prefix=dsItems_);
+  data work.&dsItems;
+    set &viyaFileExtRespLibDs;
+    where _viyaItemIdx = &itemRowGroup;
+  run;
+
+  /* Populate typeDefName, if requested */
+  %if (not %mf_isBlank(&typeDefNameVar)) %then %do;
+    %let &typeDefNameVar = %mf_getvalue(&dsItems,value,filter=%quote(p1="items" and p2="name"));
+    %if &mdebug=1 %then %put DEBUG: &=typeDefNameVar &typeDefNameVar=&&&typeDefNameVar;
+  %end;
+
+  /* Populate mediaType, if requested */
+  %if (not %mf_isBlank(&mediaTypeVar)) %then %do;
+    %let &mediaTypeVar = %mf_getvalue(&dsItems,value,filter=%quote(p1="items" and p2="mediaType"));
+    %if &mdebug=1 %then %put DEBUG: &=mediaTypeVar &mediaTypeVar=&&&mediaTypeVar;
+  %end;
+
+  /* Populate properties macro variable, if requested */
+  %if not %mf_isBlank(&propertiesVar) %then %do;
+
+    /* Filter dsItems down to the properties */
+    %local dsProperties;
+    %let dsProperties = %mf_getuniquename(prefix=dsProperties_);
+    data work.&dsProperties ( rename=(p3 = propertyName) );
+        set work.&dsItems;
+        where p2="properties" and v=1;
+    run;
+
+    /* Check for 1+ properties */
+    %if ( %mf_nobs(&dsProperties) = 0 ) %then %do;
+      %let &propertiesVar = %str();
+      %if &mdebug=1 %then %put DEBUG: &SYSMACRONAME - No Viya properties found for file suffix %str(%')&ext%str(%');
+    %end;
+    %else %do;
+      /* Properties potentially span multiple rows in the input table */
+      data _null_;
+        length
+          line $32767
+          properties $32767
+        ;
+        retain properties;
+        set &dsProperties end=last;
+        if _n_ = 1 then properties = '{';
+
+        line = cats(quote(trim(propertyName)),':');
+        /* Only strings and bools appear in properties */
+        if value not in ("true","false") then value = quote(trim(value));
+        line = catx(' ',line,value);
+        /* Add a comma separator to all except the last line */
+        if not last then line = cats(line,',');
+
+        /* Add this line to the output value */
+        properties = catx(' ',properties,line);
+
+        if last then do;
+          /* Close off the properties object and output to the macro variable */
+          properties=catx(' ',properties,'}');
+          call symputx("&propertiesVar",properties);
+        end;
+      run;
+
+      %if &mdebug=1 %then %put DEBUG: &=propertiesVar &propertiesVar=&&&propertiesVar;
+    %end;
+
+  %end;
+
+%mend mv_getViyaFileExtParms;
\ No newline at end of file