UpgradeHelper

UpgradeHelper.m

//Objective-c
//HEADER
#import <Foundation/Foundation.h>

@interface UpgradeHelper : NSObject
+(BOOL)isUpgradeAvailable:(NSString*)localVersion releasedVersion:(NSString*)releasedVersion;
@end

//IMPLEMENTATION
#import "UpgradeHelper.h"

@implementation UpgradeHelper

+(BOOL)UpgradeAvailable:(NSString*)localVersion releasedVersion:(NSString*)releasedVersion
{
    NSArray *localVersionArray = [localVersion componentsSeparatedByString:@"."];
    NSArray *releasedVersionArray = [releasedVersion componentsSeparatedByString:@"."];

    int count = fmax(localVersionArray.count, releasedVersionArray.count);
    NSString *localVersionString = @"";
    NSString *releasedVersionString = @"";
    for (int index = 0; index < count; index++)
    {
        NSString *localDigitString = (index < localVersionArray.count) ? localVersionArray[index] : @"000";
        NSString *releasedDigitString = (index < releasedVersionArray.count) ? releasedVersionArray[index] : @"000";
        localVersionString = [localVersionString stringByAppendingString:[UpgradeHelper createThreeDigitStringWithSignificantZeros:localDigitString]];
        releasedVersionString = [releasedVersionString stringByAppendingString:[UpgradeHelper createThreeDigitStringWithSignificantZeros:releasedDigitString]];
    }
    NSInteger localVersionInt = [localVersionString integerValue];
    NSInteger releasedVersionInt = [releasedVersionString integerValue];
    return localVersionInt < releasedVersionInt;
}

+(NSString*)createThreeDigitStringWithSignificantZeros:(NSString*)string;
{
    NSString *newString = [string mutableCopy];
    NSUInteger count = newString.length;
    while (count < 3)
    {
        newString = [[@"0" stringByAppendingString:newString] mutableCopy];
        count = newString.length;
    }
    return [newString copy];
}

@end

UpgradeHelper.swift

//Swift
import UIKit

@objc public class UpgradeHelper
{
    public class func isUpgradeAvailable(#localVersion:String, releasedVersion:String) -> Bool
    {
        var localVersionArray = localVersion.componentsSeparatedByString(".")
        var releasedVersionArray = releasedVersion.componentsSeparatedByString(".")

        let count = max(localVersionArray.count, releasedVersionArray.count)
        var localVersionString = ""
        var releasedVersionString = ""
        for index in 0..<count
        {
            var localDigitString:String = (index < localVersionArray.count) ? localVersionArray[index] : "000"
            var releasedDigitString:String = (index < releasedVersionArray.count) ? releasedVersionArray[index] : "000"
            localVersionString += createThreeDigitStringWithSignificantZeros(localDigitString)
            releasedVersionString += createThreeDigitStringWithSignificantZeros(releasedDigitString)
        }
        let localVersionInt = localVersionString.toInt() ?? 0
        let releasedVersionInt = releasedVersionString.toInt() ?? 0
        return localVersionInt < releasedVersionInt
    }

    private class func createThreeDigitStringWithSignificantZeros(string:String) -> String
    {
        var newString = string
        var count = countElements(newString)
        while (count < 3)
        {
            newString = "0" + newString
            count = countElements(newString)
        }
        return newString
    }
}

//For playgroud:
"TRUE"
UpgradeHelper.isUpgradeAvailable(localVersion: "99.88.77", releasedVersion: "100.100.100")
UpgradeHelper.isUpgradeAvailable(localVersion: "1.6.0", releasedVersion: "1.6.1")
UpgradeHelper.isUpgradeAvailable(localVersion: "1.6.1", releasedVersion: "2.0.5")
UpgradeHelper.isUpgradeAvailable(localVersion: "1.5", releasedVersion: "1.5.1")
UpgradeHelper.isUpgradeAvailable(localVersion: "1.5.0", releasedVersion: "1.5.1")
UpgradeHelper.isUpgradeAvailable(localVersion: "1.6.1", releasedVersion: "1.7")
UpgradeHelper.isUpgradeAvailable(localVersion: "1.6.1", releasedVersion: "1.7.0")
UpgradeHelper.isUpgradeAvailable(localVersion: "1.6.1", releasedVersion: "1.6.1.1")
UpgradeHelper.isUpgradeAvailable(localVersion: "1.6.1.0", releasedVersion: "1.6.1.1")
UpgradeHelper.isUpgradeAvailable(localVersion: "1.5", releasedVersion: "1.6.1.1")
UpgradeHelper.isUpgradeAvailable(localVersion: "1.5.0.0", releasedVersion: "1.6.1.1")

"FALSE"
UpgradeHelper.isUpgradeAvailable(localVersion: "1.6.1", releasedVersion: "1.6.0")
UpgradeHelper.isUpgradeAvailable(localVersion: "1.6.0", releasedVersion: "1.5.9")
UpgradeHelper.isUpgradeAvailable(localVersion: "1.6", releasedVersion: "1.5.9")
UpgradeHelper.isUpgradeAvailable(localVersion: "1.6.1.1", releasedVersion: "1.6.1")
UpgradeHelper.isUpgradeAvailable(localVersion: "1.6.1.1", releasedVersion: "1.6.1.0")