diff --git a/CHANGELOG.md b/CHANGELOG.md
index 787c642ad9..542f8b4ba9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ### Added
 
 - Added support for the new license key format. A proprietary key can now grant a subset of the library: a function your key does not include evaluates to a `#LIC!` error, and the matching parts of the API throw a `LicenseCapabilityMissingError`. `getAvailableFunctions()` and `getFunctionDetails()` describe only the functions your key includes. [#1728](https://github.com/handsontable/hyperformula/pull/1728)
+- Added a new function: `GESTEP`. [#1788](https://github.com/handsontable/hyperformula/pull/1788)
 
 ### Changed
 
@@ -19,6 +20,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ### Fixed
 
 - Fixed the validation of classic (25-character) license keys depending on the time zone: east of UTC, a key that expired the day before the build was released was still accepted, and west of UTC, the console message printed an expiry date one day too early. [#1728](https://github.com/handsontable/hyperformula/pull/1728)
+- Fixed the `DELTA` function returning a number for a boolean or an empty text argument instead of `#VALUE!` as Excel does; numeric text, dates and empty cells are still accepted. [#1788](https://github.com/handsontable/hyperformula/pull/1788)
+- Fixed number literals with an uppercase exponent marker, such as `=1E5` or `=1E-3`, being rejected as a parse error; the lowercase form was already accepted. [#1788](https://github.com/handsontable/hyperformula/pull/1788)
 - Fixed the `AVERAGEIF` function returning a division-by-zero error when the calculated average was `0`. [#1733](https://github.com/handsontable/hyperformula/pull/1733)
 - Fixed the localized names of `VSTACK` and `HSTACK` in 14 language packs to match Microsoft Excel. [#1748](https://github.com/handsontable/hyperformula/pull/1748)
 - Fixed the MAXPOOL and MEDIANPOOL functions throwing an uncaught `TypeError` instead of returning the `#VALUE!` error when the range dimensions are not a whole multiple of the window size and the stride. [#1718](https://github.com/handsontable/hyperformula/pull/1718)
diff --git a/src/i18n/languages/csCZ.ts b/src/i18n/languages/csCZ.ts
index fea286083c..f0cbc3e157 100644
--- a/src/i18n/languages/csCZ.ts
+++ b/src/i18n/languages/csCZ.ts
@@ -399,6 +399,7 @@ const dictionary: RawTranslationPackage = {
     'CONFIDENCE.T': 'CONFIDENCE.T',
     DEVSQ: 'DEVSQ',
     GEOMEAN: 'GEOMEAN',
+    GESTEP: 'GESTEP',
     HARMEAN: 'HARMEAN',
     CRITBINOM: 'CRITBINOM',
     PEARSON: 'PEARSON',
diff --git a/src/i18n/languages/daDK.ts b/src/i18n/languages/daDK.ts
index 9264551249..d80bc7eecc 100644
--- a/src/i18n/languages/daDK.ts
+++ b/src/i18n/languages/daDK.ts
@@ -399,6 +399,7 @@ const dictionary: RawTranslationPackage = {
     'CONFIDENCE.T': 'KONFIDENST',
     DEVSQ: 'SAK',
     GEOMEAN: 'GEOMIDDELVÆRDI',
+    GESTEP: 'GESTEP',
     HARMEAN: 'HARMIDDELVÆRDI',
     CRITBINOM: 'KRITBINOM',
     PEARSON: 'PEARSON',
diff --git a/src/i18n/languages/deDE.ts b/src/i18n/languages/deDE.ts
index 4d3d39319b..0e7eabdbb2 100644
--- a/src/i18n/languages/deDE.ts
+++ b/src/i18n/languages/deDE.ts
@@ -399,6 +399,7 @@ const dictionary: RawTranslationPackage = {
     'CONFIDENCE.T': 'KONFIDENZ.T',
     DEVSQ: 'SUMQUADABW',
     GEOMEAN: 'GEOMITTEL',
+    GESTEP: 'GESTEP',
     HARMEAN: 'HARMITTEL',
     CRITBINOM: 'KRITBINOM',
     PEARSON: 'PEARSON',
diff --git a/src/i18n/languages/enGB.ts b/src/i18n/languages/enGB.ts
index d271b732cd..6a11e06ecd 100644
--- a/src/i18n/languages/enGB.ts
+++ b/src/i18n/languages/enGB.ts
@@ -399,6 +399,7 @@ const dictionary: RawTranslationPackage = {
     'CONFIDENCE.T': 'CONFIDENCE.T',
     DEVSQ: 'DEVSQ',
     GEOMEAN: 'GEOMEAN',
+    GESTEP: 'GESTEP',
     HARMEAN: 'HARMEAN',
     CRITBINOM: 'CRITBINOM',
     'COVARIANCE.P': 'COVARIANCE.P',
diff --git a/src/i18n/languages/esES.ts b/src/i18n/languages/esES.ts
index 9c6b817b98..249208401b 100644
--- a/src/i18n/languages/esES.ts
+++ b/src/i18n/languages/esES.ts
@@ -399,6 +399,7 @@ export const dictionary: RawTranslationPackage = {
     'CONFIDENCE.T': 'INTERVALO.CONFIANZA.T',
     DEVSQ: 'DESVIA2',
     GEOMEAN: 'MEDIA.GEOM',
+    GESTEP: 'GESTEP',
     HARMEAN: 'MEDIA.ARMO',
     CRITBINOM: 'BINOM.CRIT',
     PEARSON: 'PEARSON',
diff --git a/src/i18n/languages/fiFI.ts b/src/i18n/languages/fiFI.ts
index 99ff05708f..f97bc28152 100644
--- a/src/i18n/languages/fiFI.ts
+++ b/src/i18n/languages/fiFI.ts
@@ -399,6 +399,7 @@ const dictionary: RawTranslationPackage = {
     'CONFIDENCE.T': 'LUOTTAMUSVÄLI.T',
     DEVSQ: 'OIKAISTU.NELIÖSUMMA',
     GEOMEAN: 'KESKIARVO.GEOM',
+    GESTEP: 'GESTEP',
     HARMEAN: 'KESKIARVO.HARM',
     CRITBINOM: 'BINOMIJAKAUMA.KRIT',
     PEARSON: 'PEARSON',
diff --git a/src/i18n/languages/frFR.ts b/src/i18n/languages/frFR.ts
index f7b9be45f7..9c79893d02 100644
--- a/src/i18n/languages/frFR.ts
+++ b/src/i18n/languages/frFR.ts
@@ -399,6 +399,7 @@ const dictionary: RawTranslationPackage = {
     'CONFIDENCE.T': 'INTERVALLE.CONFIANCE.STUDENT',
     DEVSQ: 'SOMME.CARRES.ECARTS',
     GEOMEAN: 'MOYENNE.GEOMETRIQUE',
+    GESTEP: 'GESTEP',
     HARMEAN: 'MOYENNE.HARMONIQUE',
     CRITBINOM: 'CRITERE.LOI.BINOMIALE',
     PEARSON: 'PEARSON',
diff --git a/src/i18n/languages/huHU.ts b/src/i18n/languages/huHU.ts
index e40219553a..600bfd2f4e 100644
--- a/src/i18n/languages/huHU.ts
+++ b/src/i18n/languages/huHU.ts
@@ -399,6 +399,7 @@ const dictionary: RawTranslationPackage = {
     'CONFIDENCE.T': 'MEGBÍZHATÓSÁG.T',
     DEVSQ: 'SQ',
     GEOMEAN: 'MÉRTANI.KÖZÉP',
+    GESTEP: 'GESTEP',
     HARMEAN: 'HARM.KÖZÉP',
     CRITBINOM: 'KRITBINOM',
     PEARSON: 'PEARSON',
diff --git a/src/i18n/languages/idID.ts b/src/i18n/languages/idID.ts
index 719cb11db6..626ce14b2d 100644
--- a/src/i18n/languages/idID.ts
+++ b/src/i18n/languages/idID.ts
@@ -399,6 +399,7 @@ const dictionary: RawTranslationPackage = {
     'CONFIDENCE.T': 'KEYAKINAN.T',
     DEVSQ: 'KUADRAT.SIMPANG',
     GEOMEAN: 'RATA.GEO',
+    GESTEP: 'GESTEP',
     HARMEAN: 'RATA.HARM',
     CRITBINOM: 'KRIT.BINOM',
     'COVARIANCE.P': 'KOVAR.P',
diff --git a/src/i18n/languages/itIT.ts b/src/i18n/languages/itIT.ts
index 1a494628f8..bdf949e9f0 100644
--- a/src/i18n/languages/itIT.ts
+++ b/src/i18n/languages/itIT.ts
@@ -399,6 +399,7 @@ const dictionary: RawTranslationPackage = {
     'CONFIDENCE.T': 'CONFIDENZA.T',
     DEVSQ: 'DEV.Q',
     GEOMEAN: 'MEDIA.GEOMETRICA',
+    GESTEP: 'GESTEP',
     HARMEAN: 'MEDIA.ARMONICA',
     CRITBINOM: 'CRIT.BINOM',
     PEARSON: 'PEARSON',
diff --git a/src/i18n/languages/nbNO.ts b/src/i18n/languages/nbNO.ts
index ff15415a98..d63e53e1ad 100644
--- a/src/i18n/languages/nbNO.ts
+++ b/src/i18n/languages/nbNO.ts
@@ -399,6 +399,7 @@ const dictionary: RawTranslationPackage = {
     'CONFIDENCE.T': 'KONFIDENS.T',
     DEVSQ: 'AVVIK.KVADRERT',
     GEOMEAN: 'GJENNOMSNITT.GEOMETRISK',
+    GESTEP: 'GESTEP',
     HARMEAN: 'GJENNOMSNITT.HARMONISK',
     CRITBINOM: 'GRENSE.BINOM',
     PEARSON: 'PEARSON',
diff --git a/src/i18n/languages/nlNL.ts b/src/i18n/languages/nlNL.ts
index c491e2f44b..da80c92fd7 100644
--- a/src/i18n/languages/nlNL.ts
+++ b/src/i18n/languages/nlNL.ts
@@ -399,6 +399,7 @@ const dictionary: RawTranslationPackage = {
     'CONFIDENCE.T': 'VERTROUWELIJKHEID.T',
     DEVSQ: 'DEV.KWAD',
     GEOMEAN: 'MEETK.GEM',
+    GESTEP: 'GESTEP',
     HARMEAN: 'HARM.GEM',
     CRITBINOM: 'CRIT.BINOM',
     PEARSON: 'PEARSON',
diff --git a/src/i18n/languages/plPL.ts b/src/i18n/languages/plPL.ts
index 6fa4f016b4..dd749dd243 100644
--- a/src/i18n/languages/plPL.ts
+++ b/src/i18n/languages/plPL.ts
@@ -399,6 +399,7 @@ const dictionary: RawTranslationPackage = {
     'CONFIDENCE.T': 'UFNOŚĆ.T',
     DEVSQ: 'ODCH.KWADRATOWE',
     GEOMEAN: 'ŚREDNIA.GEOMETRYCZNA',
+    GESTEP: 'GESTEP',
     HARMEAN: 'ŚREDNIA.HARMONICZNA',
     CRITBINOM: 'PRÓG.ROZKŁAD.DWUM',
     PEARSON: 'PEARSON',
diff --git a/src/i18n/languages/ptPT.ts b/src/i18n/languages/ptPT.ts
index 6c1e68c328..7debc3bd23 100644
--- a/src/i18n/languages/ptPT.ts
+++ b/src/i18n/languages/ptPT.ts
@@ -399,6 +399,7 @@ const dictionary: RawTranslationPackage = {
     'CONFIDENCE.T': 'INT.CONFIANÇA.T',
     DEVSQ: 'DESVQ',
     GEOMEAN: 'MÉDIA.GEOMÉTRICA',
+    GESTEP: 'GESTEP',
     HARMEAN: 'MÉDIA.HARMÔNICA',
     CRITBINOM: 'CRIT.BINOM',
     PEARSON: 'PEARSON',
diff --git a/src/i18n/languages/ruRU.ts b/src/i18n/languages/ruRU.ts
index 6b35c1ce2f..9cfa772633 100644
--- a/src/i18n/languages/ruRU.ts
+++ b/src/i18n/languages/ruRU.ts
@@ -399,6 +399,7 @@ const dictionary: RawTranslationPackage = {
     'CONFIDENCE.T': 'ДОВЕРИТ.СТЬЮДЕНТ',
     DEVSQ: 'КВАДРОТКЛ',
     GEOMEAN: 'СРГЕОМ',
+    GESTEP: 'GESTEP',
     HARMEAN: 'СРГАРМ',
     CRITBINOM: 'КРИТБИНОМ',
     PEARSON: 'PEARSON',
diff --git a/src/i18n/languages/svSE.ts b/src/i18n/languages/svSE.ts
index 5f87580087..b862c76ebf 100644
--- a/src/i18n/languages/svSE.ts
+++ b/src/i18n/languages/svSE.ts
@@ -399,6 +399,7 @@ const dictionary: RawTranslationPackage = {
     'CONFIDENCE.T': 'KONFIDENS.T',
     DEVSQ: 'KVADAVV',
     GEOMEAN: 'GEOMEDEL',
+    GESTEP: 'GESTEP',
     HARMEAN: 'HARMMEDEL',
     CRITBINOM: 'KRITBINOM',
     PEARSON: 'PEARSON',
diff --git a/src/i18n/languages/trTR.ts b/src/i18n/languages/trTR.ts
index 93c2176d37..fca31844ae 100644
--- a/src/i18n/languages/trTR.ts
+++ b/src/i18n/languages/trTR.ts
@@ -399,6 +399,7 @@ const dictionary: RawTranslationPackage = {
     'CONFIDENCE.T': 'GÜVENİLİRLİK.T',
     DEVSQ: 'SAPKARE',
     GEOMEAN: 'GEOORT',
+    GESTEP: 'GESTEP',
     HARMEAN: 'HARORT',
     CRITBINOM: 'KRİTİKBİNOM',
     PEARSON: 'PEARSON',
diff --git a/src/interpreter/functionMetadata/categories/engineering.ts b/src/interpreter/functionMetadata/categories/engineering.ts
index 04b49aca14..d8d0461e9b 100644
--- a/src/interpreter/functionMetadata/categories/engineering.ts
+++ b/src/interpreter/functionMetadata/categories/engineering.ts
@@ -129,6 +129,13 @@ export const ENGINEERING_DOCS: Record<string, FunctionDoc> = {
     documentationUrl: 'https://hyperformula.handsontable.com/docs/guide/built-in-functions.html',
     examples: ['=DELTA(5, 5)', '=DELTA(5, 4)', '=DELTA(0)'],
   },
+  GESTEP: {
+    category: 'Engineering',
+    shortDescription: 'Returns 1 if number is greater than or equal to step, otherwise returns 0.',
+    parameters: [{name: 'number', description: 'The value to compare against the step.'}, {name: 'step', description: 'The threshold value; defaults to 0 when omitted.'}],
+    documentationUrl: 'https://hyperformula.handsontable.com/docs/guide/built-in-functions.html',
+    examples: ['=GESTEP(5, 4)', '=GESTEP(3, 4)', '=GESTEP(-1)'],
+  },
   ERF: {
     category: 'Engineering',
     shortDescription: 'Returns values of the Gaussian error integral.',
diff --git a/src/interpreter/plugin/DeltaPlugin.ts b/src/interpreter/plugin/DeltaPlugin.ts
index 2585c7be70..949b3a1548 100644
--- a/src/interpreter/plugin/DeltaPlugin.ts
+++ b/src/interpreter/plugin/DeltaPlugin.ts
@@ -1,27 +1,72 @@
-/**
- * @license
- * Copyright (c) 2025 Handsoncode. All rights reserved.
- */
-
-import {ProcedureAst} from '../../parser'
-import {InterpreterState} from '../InterpreterState'
-import {InterpreterValue} from '../InterpreterValue'
-import {FunctionArgumentType, FunctionPlugin, FunctionPluginTypecheck, ImplementedFunctions} from './FunctionPlugin'
-
-export class DeltaPlugin extends FunctionPlugin implements FunctionPluginTypecheck<DeltaPlugin> {
-  public static implementedFunctions: ImplementedFunctions = {
-    'DELTA': {
-      method: 'delta',
-      parameters: [
-        {argumentType: FunctionArgumentType.NUMBER},
-        {argumentType: FunctionArgumentType.NUMBER, defaultValue: 0},
-      ]
-    },
-  }
-
-  public delta(ast: ProcedureAst, state: InterpreterState): InterpreterValue {
-    return this.runFunction(ast.args, state, this.metadata('DELTA'),
-      (left: number, right: number) => (left === right ? 1 : 0)
-    )
-  }
-}
+/**
+ * @license
+ * Copyright (c) 2025 Handsoncode. All rights reserved.
+ */
+
+import {CellError, ErrorType} from '../../Cell'
+import {ErrorMessage} from '../../error-message'
+import {ProcedureAst} from '../../parser'
+import {InterpreterState} from '../InterpreterState'
+import {getRawValue, InternalScalarValue, InterpreterValue} from '../InterpreterValue'
+import {FunctionArgumentType, FunctionPlugin, FunctionPluginTypecheck, ImplementedFunctions} from './FunctionPlugin'
+
+export class DeltaPlugin extends FunctionPlugin implements FunctionPluginTypecheck<DeltaPlugin> {
+  public static implementedFunctions: ImplementedFunctions = {
+    'DELTA': {
+      method: 'delta',
+      parameters: [
+        {argumentType: FunctionArgumentType.SCALAR},
+        {argumentType: FunctionArgumentType.SCALAR, defaultValue: 0},
+      ]
+    },
+    'GESTEP': {
+      method: 'gestep',
+      parameters: [
+        {argumentType: FunctionArgumentType.SCALAR},
+        {argumentType: FunctionArgumentType.SCALAR, defaultValue: 0},
+      ]
+    },
+  }
+
+  /**
+   * Converts an argument the way Excel does for these functions: numbers, dates, numeric text and empty cells are
+   * accepted, while a boolean or the empty text is #VALUE!. Errors are passed on. The second argument is checked first,
+   * as Excel does, so an error or a type error in it wins over one in the first argument.
+   */
+  private strictNumber(value: InternalScalarValue): number | CellError {
+    if (value instanceof CellError) {
+      return value
+    }
+    if (typeof value === 'boolean' || value === '') {
+      return new CellError(ErrorType.VALUE, ErrorMessage.NumberCoercion)
+    }
+    const coerced = this.coerceScalarToNumberOrError(value)
+    return coerced instanceof CellError ? coerced : getRawValue(coerced)
+  }
+
+  public delta(ast: ProcedureAst, state: InterpreterState): InterpreterValue {
+    return this.runFunction(ast.args, state, this.metadata('DELTA'),
+      (left: InternalScalarValue, right: InternalScalarValue) => {
+        const b = this.strictNumber(right)
+        const a = this.strictNumber(left)
+        if (b instanceof CellError) {
+          return b
+        }
+        return a instanceof CellError ? a : (a === b ? 1 : 0)
+      }
+    )
+  }
+
+  public gestep(ast: ProcedureAst, state: InterpreterState): InterpreterValue {
+    return this.runFunction(ast.args, state, this.metadata('GESTEP'),
+      (num: InternalScalarValue, step: InternalScalarValue) => {
+        const b = this.strictNumber(step)
+        const a = this.strictNumber(num)
+        if (b instanceof CellError) {
+          return b
+        }
+        return a instanceof CellError ? a : (a >= b ? 1 : 0)
+      }
+    )
+  }
+}
diff --git a/src/license/functionCapabilities.ts b/src/license/functionCapabilities.ts
index a26733ec5f..6453d92bb0 100644
--- a/src/license/functionCapabilities.ts
+++ b/src/license/functionCapabilities.ts
@@ -85,7 +85,7 @@ const UNGROUPED_FUNCTIONS = [
   'DOLLARFR', 'DPRODUCT', 'DSTDEV', 'DSTDEVP', 'DSUM', 'DVAR', 'DVARP', 'EFFECT', 'ERF', 'ERFC',
   'EXPON.DIST', 'F.DIST', 'F.DIST.RT', 'F.INV', 'F.INV.RT', 'F.TEST', 'FACT', 'FACTDOUBLE', 'FISHER',
   'FISHERINV', 'FLOOR.MATH', 'FLOOR.PRECISE', 'FORMULATEXT', 'FVSCHEDULE', 'GAMMA', 'GAMMA.DIST',
-  'GAMMA.INV', 'GAMMALN', 'GAUSS', 'GCD', 'GEOMEAN', 'HARMEAN', 'HEX2BIN', 'HEX2OCT', 'HYPGEOM.DIST',
+  'GAMMA.INV', 'GAMMALN', 'GAUSS', 'GCD', 'GEOMEAN', 'GESTEP', 'HARMEAN', 'HEX2BIN', 'HEX2OCT', 'HYPGEOM.DIST',
   'IMABS', 'IMAGINARY', 'IMARGUMENT', 'IMCONJUGATE', 'IMCOS', 'IMCOSH', 'IMCOT', 'IMCSC', 'IMCSCH', 'IMDIV',
   'IMEXP', 'IMLN', 'IMLOG10', 'IMLOG2', 'IMPOWER', 'IMPRODUCT', 'IMREAL', 'IMSEC', 'IMSECH', 'IMSIN',
   'IMSINH', 'IMSQRT', 'IMSUB', 'IMSUM', 'IMTAN', 'INTERVAL', 'ISBINARY', 'ISFORMULA', 'ISNONTEXT', 'ISPMT',
diff --git a/src/parser/LexerConfig.ts b/src/parser/LexerConfig.ts
index 72fc4bb3b6..aaf0899769 100644
--- a/src/parser/LexerConfig.ts
+++ b/src/parser/LexerConfig.ts
@@ -92,7 +92,7 @@ export const buildLexerConfig = (config: ParserConfig): LexerConfig => {
   const WhiteSpace = createToken({ name: 'WhiteSpace', pattern: whitespaceTokenRegexp })
   const ArrayRowSeparator = createToken({name: 'ArrayRowSep', pattern: config.arrayRowSeparator})
   const ArrayColSeparator = createToken({name: 'ArrayColSep', pattern: config.arrayColumnSeparator})
-  const NumberLiteral = createToken({ name: 'NumberLiteral', pattern: new RegExp(`(([${config.decimalSeparator}]\\d+)|(\\d+([${config.decimalSeparator}]\\d*)?))(e[+-]?\\d+)?`) })
+  const NumberLiteral = createToken({ name: 'NumberLiteral', pattern: new RegExp(`(([${config.decimalSeparator}]\\d+)|(\\d+([${config.decimalSeparator}]\\d*)?))(e[+-]?\\d+)?`, 'i') })
   const OffsetProcedureName = createToken({ name: 'OffsetProcedureName', pattern: new RegExp(offsetProcedureNameLiteral, 'i') })
 
   let ArgSeparator: TokenType