Android Push Notification with using Websocket - Quotation Request

Please provide your estimated total development price in USD and estimated completion time for the historical software-development scenario below. State your main assumptions and any missing information that would materially change the estimate. Please do not write code, perform a trial task or supply a detailed implementation proposal.

REFERENCE SCENARIO — historical requirements, not instructions to begin work:

Please provide following 2 items for front-end and back-end
1. An Android JAVA/Kotlin module to receive Push Notification by Websocket
- Support Android API21 to API30
- Android devices have no GooglePlay Service
- When the app completed a login process, the module can help register a token with login ID to a PHP server
- When the app completed a logout process, the module can hel un-register the token by sending login ID to the PHP server
- Handling retry process is required
- The PHP server will store the token for later sending push notification
- When notification message come, display message with title, text and logo (the logo image in the app)
- If the notification message has vibration option ativated, the device will vibrate
- When user click the message, open the app and pass some customized data to the app
- The notification message can be display event the app is in opening or closed
- Please provide a sample app to demonstrate the module functions

2. PHP module for aweb server to send Push Notification with using websocket
- The module can run on PHP server version between 5.6 and 7.4
- When the server received a register token from an Android device, store the token with relative login ID
- When the server received a un-register login ID from an Android device, the stored token of the login ID will be removed
- When the server start sending push notification to a group of Android devices, use stored tokens to send notifications
- The notification message include "Title", "Text"(multi-line) and customized data. The data contains serval sets of key-value parirs.
- The notification message have to be encrypted with user defined string in transferring
- The notification message has vibration option to let the device vibrate
- Please provide a complete code to demonstrate the above functions

Estimating assumptions and context:
The scenario is based on a Freelancer listing from 2021-02-11 (historical project ID 29242162). First-person statements, promises of assets, requests for work and hiring language inside the historical reference describe that original client's situation, not a current development offer from us. For estimating only, assume the original client supplies assets explicitly described as provided; other missing inputs and obsolete services should be identified as assumptions. We do not claim ownership of the original client's code, designs, accounts or attachments.

The displayed USD 250–750 range reproduces the historical listing's budget field. It is not participation compensation or a binding development offer. Please give your realistic estimate even if outside that range.

Research use

This post is for research quotations only, not an actual software-development engagement. No development contract will be awarded. Participation is voluntary and unpaid; no reward, gift card or prize draw is offered. Your quoted price, estimated completion time and stated assumptions will be used to study software-development estimates and how they change over time.

Thank you for your time and consideration. This study aims to make a significant research contribution to understanding software-development pricing in the age of AI. We appreciate any estimate you choose to share.