Update solidity

.solhint.json

@@ -1,7 +1,7 @@
 {
   "extends": "solhint:all",
   "rules": {
-    "compiler-version": ["error","^0.6.10"],
+    "compiler-version": ["error","^0.8.8"],
     "state-visibility": "error",
     "no-empty-blocks": "error",
     "check-send-result": "error",

contracts/IBountyV2.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager Interfaces.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface IBountyV2 {
 
@@ -44,4 +44,4 @@ interface IBountyV2 {
     function estimateBounty(uint nodeIndex) external view returns (uint);
     function getNextRewardTimestamp(uint nodeIndex) external view returns (uint);
     function getEffectiveDelegatedSum() external view returns (uint[] memory);
-}
+}

contracts/IConstantsHolder.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager Interfaces.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface IConstantsHolder {
 

contracts/IContractManager.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager Interfaces.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface IContractManager {
     /**

contracts/IDecryption.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface IDecryption {
     function encrypt(uint256 secretNumber, bytes32 key) external pure returns (bytes32);

contracts/IKeyStorage.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 import "./ISkaleDKG.sol";
 
@@ -29,7 +29,7 @@ interface IKeyStorage {
         bytes32[2] publicKey;
         bytes32 share;
     }
-    
+
     function deleteKey(bytes32 schainHash) external;
     function initPublicKeyInProgress(bytes32 schainHash) external;
     function adding(bytes32 schainHash, ISkaleDKG.G2Point memory value) external;

contracts/IMintableToken.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface IMintableToken {
     function mint(
@@ -30,4 +30,4 @@ interface IMintableToken {
     )
         external
         returns (bool);
-}
+}

contracts/INodeRotation.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface INodeRotation {
     /**

contracts/INodes.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 import "./utils/IRandom.sol";
 

contracts/IPaymasterController.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface IPaymasterController {
     function addSchain(string calldata name) external;

contracts/IPermissions.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface IPermissions {
     function initialize(address contractManagerAddress) external;

contracts/IPricing.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface IPricing {
     function initNodes() external;

contracts/ISchains.sol

@@ -19,15 +19,15 @@
     along with SKALE Manager Interfaces.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface ISchains {
 
     struct SchainOption {
         string name;
         bytes value;
     }
-    
+
     /**
      * @dev Emitted when an schain is created.
      */

contracts/ISchainsInternal.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager Interfaces.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 import "./INodes.sol";
 

contracts/ISkaleDKG.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface ISkaleDKG {
 

contracts/ISkaleManager.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface ISkaleManager {
     /**
@@ -38,7 +38,7 @@ interface ISkaleManager {
         uint bounty,
         uint previousBlockEvent
     );
-    
+
     function createNode(
         uint16 port,
         uint16 nonce,

contracts/ISkaleVerifier.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 import "./ISkaleDKG.sol";
 

contracts/ISlashingTable.sol

@@ -19,14 +19,14 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface ISlashingTable {
     /**
      * @dev Emitted when penalty was added
      */
     event PenaltyAdded(uint indexed offenseHash, string offense, uint penalty);
-    
+
     function setPenalty(string calldata offense, uint penalty) external;
     function getPenalty(string calldata offense) external view returns (uint);
 }

contracts/ISyncManager.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface ISyncManager {
     struct IPRange {

contracts/IWallets.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager Interfaces.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface IWallets {
     receive() external payable;

contracts/delegation/IDelegatableToken.sol

@@ -19,25 +19,25 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 /**
  * @dev Interface of the SkaleToken contract.
  */
 interface IDelegatableToken {
-    
+
     /**
      * @dev Returns and updates the amount of locked tokens of a given account `wallet`.
      */
     function getAndUpdateLockedAmount(address wallet) external returns (uint);
-    
+
     /**
      * @dev Returns and updates the amount of delegated tokens of a given account `wallet`.
      */
     function getAndUpdateDelegatedAmount(address wallet) external returns (uint);
-    
+
     /**
      * @dev Returns and updates the amount of slashed tokens of a given account `wallet`.
      */
     function getAndUpdateSlashedAmount(address wallet) external returns (uint);
-}
+}

contracts/delegation/IDelegationController.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface IDelegationController {
     enum State {
@@ -86,7 +86,7 @@ interface IDelegationController {
     event UndelegationRequested(
         uint delegationId
     );
-    
+
     function getAndUpdateDelegatedToValidatorNow(uint validatorId) external returns (uint);
     function getAndUpdateDelegatedAmount(address holder) external returns (uint);
     function getAndUpdateEffectiveDelegatedByHolderToValidator(address holder, uint validatorId, uint month)

contracts/delegation/IDelegationPeriodManager.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface IDelegationPeriodManager {
     /**
@@ -29,7 +29,7 @@ interface IDelegationPeriodManager {
         uint length,
         uint stakeMultiplier
     );
-    
+
     function setDelegationPeriod(uint monthsCount, uint stakeMultiplier) external;
     function stakeMultipliers(uint monthsCount) external view returns (uint);
     function isDelegationPeriodAllowed(uint monthsCount) external view returns (bool);

contracts/delegation/IDistributor.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface IDistributor {
     /**
@@ -48,7 +48,7 @@ interface IDistributor {
         uint validatorId,
         uint amount
     );
-    
+
     function getAndUpdateEarnedBountyAmount(uint validatorId) external returns (uint earned, uint endMonth);
     function withdrawBounty(uint validatorId, address to) external;
     function withdrawFee(address to) external;

contracts/delegation/ILocker.sol

@@ -19,14 +19,14 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 /**
  * @dev Interface of the Locker functions.
  */
 interface ILocker {
     /**
-     * @dev Returns and updates the total amount of locked tokens of a given 
+     * @dev Returns and updates the total amount of locked tokens of a given
      * `holder`.
      */
     function getAndUpdateLockedAmount(address wallet) external returns (uint);

contracts/delegation/IPunisher.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface IPunisher {
     /**
@@ -37,7 +37,7 @@ interface IPunisher {
         address wallet,
         uint amount
     );
-    
+
     function slash(uint validatorId, uint amount) external;
     function forgive(address holder, uint amount) external;
     function handleSlash(address holder, uint amount) external;

contracts/delegation/ITimeHelpers.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface ITimeHelpers {
     function calculateProofOfUseLockEndTime(uint month, uint lockUpPeriodDays) external view returns (uint timestamp);

contracts/delegation/ITokenState.sol

@@ -19,7 +19,7 @@
     along with SKALE Manager.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-pragma solidity >=0.6.10 <0.9.0;
+pragma solidity >=0.8.8 <0.9.0;
 
 interface ITokenState {
     /**
@@ -35,7 +35,7 @@ interface ITokenState {
     event LockerWasRemoved(
         string locker
     );
-    
+
     function removeLocker(string calldata locker) external;
     function addLocker(string memory locker) external;
 }