Please tell me which differences between masternodes and secure nodes? Are they the same or different?

Secure Nodes improves network security - Whole communication is encrypted and secured with secure nodes, which is not the case with typical master nodes who are vulnerable, and can be compromised in certain cases.
Secure nodes are profitabil 3.5% from every block is reserved as reward for nodes and this number is lower when you compare it with other projects with master nodes, profitability was not main concern in case of Zen.
https://blog.zensystem.io/secure-nodes-why-are-they-important/

Possibilities of secure nodes are beyond transactions, messaging and publishing..And many new good ideas can be implemented.

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This is for one payment period, and if you do not meet this requirement you won't be paid. Better luck in the next payment period.

Earnings
An earning period is based upon block time. It is the amount of time between 576 blocks which is approximately 24 hours. When an earning period ends each active node is checked and any node with exceptions or downtime causing the node to be available less than 92% of the earning period is excluded from the earnings pool. A node with greater than 92% availability but with some downtime or exceptions will have the amount of time subtracted from their allocation. These small subtractions help offset the fees incurred with making the payments.

A payment administrator on a weekly basis reviews the earnings to ensure they were generated correctly and marks them to be paid.

Coins are then transferred to a payment address and the payment is made. No funds are stored on the server. This process may be automated at a later time.

please answer on some questions about securenode configuration, haven't found this in any tutorial

is secnodetracker only available on testnet only, so i'm unable to configure securenode, using my mainnet wallet balance? what would be with my main wallet balance if i switch it to testnet?

For all enthusiasts who would like to share their opinion with us how system should and can be improved can do this here https://forum.zensystem.io/t/ideas-bucket/810. All ideas are welcomed and some may be lead toward proposal and finally fundings.

Does Zencash have plans to support instant transactions through securenodes in the future?

Everyone's too ready for a short. The REKTs are already piling up. I wouldn't be surprised if this plays out slightly another way   

If you have more then 43 ZEN - i can UP node for you.Let me know in telegram or PM here  @gugulme

Ecли вы дepжитe бoльшe 43 зeн, я мoгy пoднять для вac нoдy. Oбpaщaйтecь в тeлeгpaм @gugulme или ЛC.

Thanks

We are waiting for Secure Nodes to go online (mainnet) announced for November 30th.
You can get all details from our latest video update -> https://www.youtube.com/watch?v=TvZ1PWakWCA