No. As of now, notifications are sent only via Email
Ability to receive reminder for a particular task is not available. However, you can get to know the status of all the tasks, meetings and milestones assigned to you, with the help of Email My Activities option.

To change the task's name in Dependency View, click the task name to update the task name and press Enter Key.
Notification is sent to the task owners when the percentage completion is updated to 100% - provided Send Mail Notification option is enabled. Else, no notification is sent to the task owners.
It is possible to collapse the task lists. For that, you can click on the Collapse symbol – displayed to the left of the task list name.
Tasks assigned to you will be displayed in your Google Calendar, only when the task is created with duration (Start & End date) and Add to Google Calendar option is enabled.
Note: Add to Google Calendar option will be available only for the Google Apps users.
When using the Print option – available at the top right side of the page – only empty page is displayed. This is because of the Flash based Gantt chart.
However, you can right click on the Gantt chart and click Print Chart option.
All the seven days of the week are taken into account. Option to avoid weekend, National Holidays is yet to be supported.
Milestones can be created only with start and end date. Option to create milestones for a project without duration is yet to be supported.
Project Members – irrespective of their role – can view all the tasks. Changing the access permissions of the project members is not possible.
To know more about the access privileges, visit User Roles and Access Privileges.
Send an email infers to notifying the selected task owners, about the task via email. This will help the user(s) to know that a task has been assigned to them, even without logging into the projects account.
As of now, there's no centralized option to turn-off the notification option.
By default, Client user will be able to access the tasks that are associated with the External Milestone/ Task List.
In your case, client user is unable view the tasks, as the milestone/ task list to which the task is associated might be Internal. You can edit the milestones/task list and change the flag to External.
To add a file to a task :

Select Click Here option. Browse and add the file directly to the task

Subtasks are available only for paid customers of Enterprise and Premium plans of Zoho Projects. If you are in Free Plan, then we request you to upgrade your account to see subtasks.
For more details contact us at support@zohoprojects.com
If you are the Portal Owner or Administrator and your projects portal is in the Enterprise plan, you will be able to see the Resource Availability / Utilization chart across all projects from the Reports Tab on the home page.
If you are the Portal Owner or Administrator and your projects portal is in the Enterprise plan, you will be able to see the Gantt Chart across all projects from the Reports Tab in the home page.

When a task is edited, the updated task shifts to the top of the page and gets highlighted in yellow color. This is done to highlight the updated task from the rest of the tasks listed in the page.
Currently the ability to reorder subtasks is not supported. However, we have plans of supporting this feature in our future updates.
You will be able to add subtask to a task only if your projects portal/account is in the Premium or Enterprise plan.
If your Zoho Projects account is a paid Premium or Enterprise plan but still you are unable to add subtask then write to us at support@zohoprojects.com
It is not possible to move a subtask from one parent task to another. However, you can follow the below workaround to move a subtask :
Drag & Drop function is supported in the Gantt Chart. i.e The users can update the task's duration using this function. Creating dependency is not possible via drag and drop option.
As per the existing design the maximum period supported on the Gantt chart is 12 months. Viewing the report for more than 12 months on the Gantt chart is not possible.
You can mark all the tasks within a task list as completed, change the priority, ownership and move them to a different task list. But it is not possible to update the percentage.
To make bulk changes, follow the steps below :

It is not possible to delete tasks from the Task Dependency view. Tasks can be deleted only from the Tasks section.
With the current design, a copy of the notification mail will be sent to you when you update the task. Option to stop receiving this notification mail is not supported yet.
It is not possible to change the priority names as it is predefined. Customization is not supported yet.
Currently it is not possible to add new priority because customization is yet to be supported for tasks.