Update Google Apps Scripts Library Version on Client Side?

Sorry for answering after 1 year, If i understand, you have a Script Project which is a library for several users project and your problem is to deploy a livrary version in every client project.

As Alan Wells says, you just have to replace the manifest of each client project.

Your manifest is a appsscript.json file. (you could show/hide the manifest file in a project)

Manifest file syntax :

{
  "timeZone": "XXX",
  "dependencies": {
         **** SOME dependencies you need for the client**** 
       ,
    "libraries": [{
      "userSymbol": "MAIN_SCRIPT_NAME",
      "libraryId": "MAIN_SCRIPT_ID",
      "version": "MAIN_SCRIPT_VERSION"
    }]
  },
  "exceptionLogging": "STACKDRIVER"
}

You could use CLASP to manage your script easily.

In your example, in clasp, you create a master folder for your project and a subfolder for every Clients Script. You need to sync every subfolder to his GoogleAppsScript. The initialisation could be long and boring, but with a little shell you be able to push the manifest to every client script with on click/script..

You just have to modify the manifest into your Master Folder and run a script like :

for x in `ls -d SubFolder*`; do (cp appsscript.json $x ; cd $x; clasp push -f >/dev/null ; cd ..; echo "Update done on "$x) ; done

Now you can update the manifest for every client, Library version is available, but the dependencies too... (if you need start some new, or end others)

You can update the version with a trigger on the client-side or using a webapp with the ScriptSync library, something like this:

function updateLibraryVersion(libraryId='', libraryName='', version) {
  const script_id = ScriptApp.getScriptId();
  const current_script_json = ScriptSync.getScriptContent(script_id);
  var appsscript_json = current_script_json.files.find(file => {
      return file.name === "appsscript"
  });

  if(appsscript_json) {
    appsscript_json = JSON.parse(appsscript_json.source);
    var library = appsscript_json.dependencies?.libraries?.find(lib => {
        return (
            lib.libraryId === libraryId
            || lib.userSymbol === libraryName
        );
    });

    if(library) {
      let new_version = version || Number(library.version) + 1;
      library.version = (new_version).toString();
      appsscript_json.source = JSON.stringify(appsscript_json, null, 2);
      const updater = ScriptSync.assignTemplate();
      updater.addFileToUserJson("appsscript", appsscript_json);
      updater.viewChanges(370);
      Utilities.sleep(20000);   // waiting for interruption by user (if needed)
      return updater.commit();  // after, apply the changes
    }
  }
  return false;
}

function do(e) {
  // ....
  const libraryId    = "your_library_script_id";
  const libraryName  = "LibraryNameUsersDefined";
  const updateResult = updateLibraryVersion(libraryId, libraryName, e.version);
  console.log(updateResult);
  //...
}

If using a trigger:

function setTriggers() {
  ScriptApp.newTrigger("t_updateVersion").timeBased()
    .everyDays(1)
    .atHour(1).create();
}

function t_updateVersion() {
  /* Initialize your template script */
  const template_script_id = "your_template_script_id";
  const updater = ScriptSync.assignTemplate(template_script_id);

  // template_appsscript - any file in your template (representing appsscript)
  // script_appsscript - appsscript in the current user's script (use 'appsscript' file this)
  const match = updater.compareFilesByContent(template_appsscript, script_appsscript);

  if (!match) {
    const updateResult = updateLibraryVersion(libraryId, libraryName);
    // or copy the whole file (not the best idea, but as an option)
    // because the user could set his own code here
    const fileToCopy = 'appsscript';
    updater.AddNewFile("template_appsscript", "appsscript", "json");
  }
}

Also, in the best way, using these examples, you can extract a new version of the library from the template file and set it to the user script "appsscript" file. Not tested (check it first):

/**
 * ScriptSync id (from hint while text 'updater'): 
 * @param {MRaUrgsx725qu8gUzKJlDXtz8VMKMxn5x.ScriptSync}  updater
 */
function updateLibraryVersionUpdater(updater, libraryId='', libraryName='', version) {
  const script_id = ScriptApp.getScriptId();
  const current_script_json = ScriptSync.getScriptContent(script_id);
  var appsscript_json = current_script_json.files.find(file => {
      return file.name === "appsscript"
  });

  if(appsscript_json) {
    appsscript_json = JSON.parse(appsscript_json.source);
    var library = appsscript_json.dependencies?.libraries?.find(lib => {
        return (
            lib.libraryId === libraryId
            || lib.userSymbol === libraryName
        );
    });

    if(library) {
      library.version = version;
      appsscript_json.source = JSON.stringify(appsscript_json, null, 2);
      updater.addFileToUserJson("appsscript", appsscript_json);
      return updater.commit();  // apply the changes
    }
  }
  return false;
}

/**
 * ScriptSync id: 
 * @param {MRaUrgsx725qu8gUzKJlDXtz8VMKMxn5x.ScriptSync}  updater
 */
function getLibraryVersion(updater, libraryId, libraryName) {
  const template_app_json = updater.getFileFromTemplate("appsscript", sourceOnly=true);
  if (template_app_json) {
    template_app_json = JSON.parse(template_app_json);
    var library = template_app_json.dependencies?.libraries?.find(lib => {
        return (
            lib.libraryId === libraryId
            || lib.userSymbol === libraryName
        );
    });
    return library.version;
  }
}

function t_updateVersion() {
  var updateResult;
  /* Initialize your template script and library */
  const template_script_id = "your_template_script_id";
  const updater = ScriptSync.assignTemplate(template_script_id);

  // template_appsscript - any file in your template (representing appsscript)
  // script_appsscript - appsscript in the current user's script (use 'appsscript' file this)
  const match = updater.compareFilesByContent(template_appsscript, script_appsscript);

  if (!match) {
    const libraryVersion = getLibraryVersion(updater, libraryId, libraryName);
    if (libraryVersion)
        updateResult = updateLibraryVersionUpdater(updater, libraryId, libraryName, libraryVersion);
  }

  return updateResult || false;
}