# Priority Upgrade

## What is it?

Every credit-token (CT) is minted with Middle priority by default. A holder can **upgrade** any number of their tokens to High priority at any time by paying a fee. In a default scenario, High tokens are repaid first (principal + interest), so they are safer.

<details>

<summary>Capacity rule (Advanced Users)</summary>

To keep the pool balanced, no more than **⅓ of all CT-tokens** may sit in the High bucket.\
We measure the current fill level u\_t:

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Where:

* **H\_t:** number of High-priority CTs in the pool.
* **T\_t**​ – total CT supply (High + Middle + Low).\\

If **u\_t = 1** the High bucket is full; no further upgrades are allowed until more Middle tokens appear (e.g., after a new stage).

**Example**\
Before a stage: 1000 High, 3 500 Middle, 500 Low\
u\_t = 1000 / \[(1/3) x 5000] = 0.60\
After minting 5000 new Middle tokens:\
u\_t = 1000 / \[(1/3) x 10000] = 0.30: room to upgrade again.

</details>

<details>

<summary>Upgrade Price (Advanced Users)</summary>

The cost to lift one CT from Middle → High grows linearly with the bucket fill:

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<figure><picture><source srcset="https://1754918713-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FexRng6kSElqCZX6yLysp%2Fuploads%2Fc5TnpQtwTSqIv15RcPdd%2Fp_sl_ut_dark.png?alt=media&#x26;token=958c0315-0438-42fa-a7fd-f8d07c6bcb45" media="(prefers-color-scheme: dark)"><img src="https://lh7-rt.googleusercontent.com/docsz/AD_4nXemwFOop13IdYmYcvIt_5vvgoyOTAA_EDESNBKEQDeZaeJKqUjPyL7nDtMiD7I-AmpGh6sjxqLtgsCdch-8zqTuwQVam7C5vtXMyijGorQ5-8jqzGyMxQtm1bxpJ9Rlyh_YYIDsQg?key=uyWe8rY2jy2nS4gSFfqFJ_Vw" alt=""></picture><figcaption></figcaption></figure>

Where:

* **C\_nom**: CT’s face value (e.g., “10” in **$CT\_ProjectXXX\_10…**).
* **a**: minimum premium (fraction of face value).
* **b:** slope: how much the premium rises as High fills up.
* **P\_average($L):** average price of mint of one $8LENDS in bonding-curve P\_mint (see [**P\_average**](https://8lends.gitbook.io/8lends.io/usd8lends-token-utility-models/broken-reference)).&#x20;

Holders may pay in **USDС/EUR** or directly in **$8LENDS** at the on-chain conversion above.

</details>

<details>

<summary>Other Rules</summary>

* Upgrades are only possible **from Middle → High** (never from Low).
* Tokens chosen for upgrade must mature one day before the loan’s due date.
* No upgrades once the Project is declared in **default**.
* A holder can **rebalance**: upgrade some CTs and downgrade others in the same wallet.
* Fees collected for upgrades are either
  1. used to top-up lower priorities, **or**
  2. burned outright (see [**Priority Downgrade**](https://8lends.gitbook.io/8lends.io/usd8lends-token-utility-models/broken-reference)).

High-priority CTs enjoy first-loss protection: in default they are paid out ahead of Middle and Low stages.

</details>
